@scsi: yes. The story is: my server was working properly incl. MySQL. Unfortunately, the ISP did not installed the 'quota' command and had to reinstall DA. After that I cannot use it.
OK, I did what you suggested - here is the result:
serwer:~# cd /usr/local/directadmin/custombuild
serwer:/usr/local/directadmin/custombuild# ./build update
--2011-01-25 20:02:07--
http://files.directadmin.com/services/custombuild/1.1/custombuild.tar.gz
Resolving files.directadmin.com... 72.35.85.222
Connecting to files.directadmin.com|72.35.85.222|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 103676 (101K) [application/x-gzip]
Saving to: `./custombuild.tar.gz'
100%[======================================>] 103,676 116K/s in 0.9s
2011-01-25 20:02:08 (116 KB/s) - `./custombuild.tar.gz' saved [103676/103676]
extracting custombuild.tar.gz for 1.1 ...
custombuild/
custombuild/build
custombuild/configure/
custombuild/configure/pureftpd/
custombuild/configure/pureftpd/configure.pureftpd
custombuild/configure/ap1/
custombuild/configure/ap1/configure.php5
custombuild/configure/ap1/configure.apache_ssl
custombuild/configure/ap1/conf/
custombuild/configure/ap1/conf/mime.types
custombuild/configure/ap1/conf/httpd.conf
custombuild/configure/ap1/conf/extra/
custombuild/configure/ap1/conf/extra/httpd-vhosts.conf
custombuild/configure/ap1/conf/extra/httpd-deflate.conf
custombuild/configure/ap1/conf/extra/httpd-multilang-errordoc.conf
custombuild/configure/ap1/conf/extra/httpd-info.conf
custombuild/configure/ap1/conf/extra/httpd-alias.conf
custombuild/configure/ap1/conf/extra/httpd-userdir.conf
custombuild/configure/ap1/conf/extra/httpd-languages.conf
custombuild/configure/ap1/conf/extra/httpd-default.conf
custombuild/configure/ap1/conf/extra/httpd-autoindex.conf
custombuild/configure/ap1/conf/extra/directadmin-vhosts.conf
custombuild/configure/ap1/conf/extra/httpd-ssl.conf
custombuild/configure/ap1/conf/magic
custombuild/configure/ap1/configure.php4
custombuild/configure/ap2/
custombuild/configure/ap2/configure.php5
custombuild/configure/ap2/conf/
custombuild/configure/ap2/conf/httpd.conf_2.0
custombuild/configure/ap2/conf/mime.types
custombuild/configure/ap2/conf/httpd.conf
custombuild/configure/ap2/conf/extra/
custombuild/configure/ap2/conf/extra/httpd-vhosts.conf
custombuild/configure/ap2/conf/extra/httpd-deflate.conf
custombuild/configure/ap2/conf/extra/httpd-mpm.conf
custombuild/configure/ap2/conf/extra/httpd-multilang-errordoc.conf
custombuild/configure/ap2/conf/extra/httpd-mpm.conf_2.0
custombuild/configure/ap2/conf/extra/httpd-info.conf
custombuild/configure/ap2/conf/extra/httpd-alias.conf
custombuild/configure/ap2/conf/extra/httpd-userdir.conf
custombuild/configure/ap2/conf/extra/httpd-languages.conf
custombuild/configure/ap2/conf/extra/httpd-dav.conf
custombuild/configure/ap2/conf/extra/httpd-default.conf
custombuild/configure/ap2/conf/extra/httpd-autoindex.conf
custombuild/configure/ap2/conf/extra/directadmin-vhosts.conf
custombuild/configure/ap2/conf/extra/httpd-ssl.conf
custombuild/configure/ap2/conf/extra/httpd-manual.conf
custombuild/configure/ap2/conf/magic
custombuild/configure/ap2/cert_config
custombuild/configure/ap2/configure.apache
custombuild/configure/ap2/configure.php4
custombuild/configure/dovecot/
custombuild/configure/dovecot/dovecot.conf
custombuild/configure/proftpd/
custombuild/configure/proftpd/configure.proftpd
custombuild/configure/suphp/
custombuild/configure/suphp/configure.php5
custombuild/configure/suphp/configure.suphp
custombuild/configure/suphp/configure.php4
--2011-01-25 20:02:08--
http://files.directadmin.com/services/custombuild/versions.txt
Resolving files.directadmin.com... 72.35.85.222
Connecting to files.directadmin.com|72.35.85.222|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 4466 (4.4K) [text/plain]
Saving to: `./versions.txt'
100%[======================================>] 4,466 --.-K/s in 0.01s
2011-01-25 20:02:09 (385 KB/s) - `./versions.txt' saved [4466/4466]
File already exists: servers.txt
MD5 Checksum on servers.txt passed.
File already exists: httpd-2.2.17.tar.gz
MD5 Checksum on httpd-2.2.17.tar.gz passed.
File already exists: httpd_2
File already exists: httpd_2_freebsd
File already exists: httpd_2_debian
File already exists: mime.types
File already exists: mod_perl-2.0.4.tar.gz
MD5 Checksum on mod_perl-2.0.4.tar.gz passed.
File already exists: curl-7.21.3.tar.gz
MD5 Checksum on curl-7.21.3.tar.gz passed.
File already exists: pcre-8.10.tar.gz
MD5 Checksum on pcre-8.10.tar.gz passed.
File already exists: libmcrypt-2.5.8.tar.gz
MD5 Checksum on libmcrypt-2.5.8.tar.gz passed.
File already exists: mhash-0.9.9.9.tar.gz
MD5 Checksum on mhash-0.9.9.9.tar.gz passed.
File already exists: freetype-2.4.4.tar.gz
MD5 Checksum on freetype-2.4.4.tar.gz passed.
File already exists: libiconv-1.13.1.tar.gz
MD5 Checksum on libiconv-1.13.1.tar.gz passed.
File already exists: libxml2-2.7.6.tar.gz
MD5 Checksum on libxml2-2.7.6.tar.gz passed.
File already exists: libxslt-1.1.26.tar.gz
MD5 Checksum on libxslt-1.1.26.tar.gz passed.
File already exists: icu4c-4_4_1-src.tgz
MD5 Checksum on icu4c-4_4_1-src.tgz passed.
File already exists: php-5.2.17.tar.gz
MD5 Checksum on php-5.2.17.tar.gz passed.
File already exists: php-5.2.17-mail-header.patch
MD5 Checksum on php-5.2.17-mail-header.patch passed.
File already exists: webalizer-2.23-03-src.tgz
File already exists: suphp-0.7.1.tar.gz
MD5 Checksum on suphp-0.7.1.tar.gz passed.
File already exists: dovecot-2.0.9.tar.gz
MD5 Checksum on dovecot-2.0.9.tar.gz passed.
File already exists: dovecot.boot
File already exists: dovecot.boot.freebsd
File already exists: dovecot.boot.debian
File already exists: dovecot.conf
File already exists: exim.conf.dovecot.patch
MD5 Checksum on exim.conf.dovecot.patch passed.
File already exists: autoconf-2.67.tar.gz
MD5 Checksum on autoconf-2.67.tar.gz passed.
File already exists: m4-1.4.15.tar.gz
MD5 Checksum on m4-1.4.15.tar.gz passed.
File already exists: automake-1.11.1.tar.gz
MD5 Checksum on automake-1.11.1.tar.gz passed.
File already exists: libtool-2.4.tar.gz
MD5 Checksum on libtool-2.4.tar.gz passed.
serwer:/usr/local/directadmin/custombuild# ./build clean
serwer:/usr/local/directadmin/custombuild# ./build mysql d
ls: cannot access */: No such file or directory
Stopping mysqld ...
Stopping mysqld: [ FAILED ]
Starting mysqld: [ OK ]
Giving mysqld a few seconds to start up...
nohup: redirecting stderr to stdout
Looking for 'mysql' as: /usr/local/mysql/bin/mysql
Looking for 'mysqlcheck' as: /usr/local/mysql/bin/mysqlcheck
Running 'mysqlcheck'...
/usr/local/mysql/bin/mysqlcheck: Got error: 2002: Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2) when trying to connect
FATAL ERROR: Upgrade failed
Restarting MySQL.
Stopping mysqld: [ FAILED ]
Starting mysqld: [ OK ]
It is recommended to do "./build php n" after MySQL update.
nohup: redirecting stderr to stdout
serwer:/usr/local/directadmin/custombuild#