ERROR while trying to add user 'alias'

[kees13]

All, can someone help me with this.

Checking for the user 'alias'...
Trying to add user 'alias'...
ERROR while trying to add user 'alias'
Check the error reason(see log file: /tmp/psa_7.5.4_Debian_3.1_build75050824.12_installing.log), fix and try again

Aborting...

dpkg: error processing /var/cache/apt/archives/psa_7.5.4-debian3.1.build75050824.12_i386.deb (--unpack):
subprocess pre-installation script returned error exit status 1
Errors were encountered while processing:
/var/cache/apt/archives/psa-qmail_1.03-debian3.1.build75060321.20_i386.deb
/var/cache/apt/archives/psa_7.5.4-debian3.1.build75050824.12_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)
ERROR: Install command execution failed
ERROR: Installation failed

thanks