What version of vpopmail? There might be a problem with 5.3.26, can you try 5.3.25 and report back on the problem? You'll have to recompile qmailadmin after installing vpopmail 5.3.25.5.3.26. Will setup 5.3.25 and try with it.
cdb.
Are you using MySQL or cdb to store user information?
