After trying tikiwiki for some days i ended up with some problems using webmail.
ERROR: se.i-team.de> -> Goto Configuration.
Some investigation led me to titkiwi/lib/webmail/pop3ph, line 94. Changing it to $this->greeting = @fgets($this->connection); did the trick (might be a good idea to read the complete line from pop3 server everywhere, as php >4.3 does with fgets($connection)).
This is because of my pop3 greeting string from cyrus imapd is quite long (more than 100 chars). So maybe this error is not that common.
I didn't bother if >100 is beyond rfc, though.
I'm using a cvs version as of 2004-03-05.
If this is not the right place to address such a problem, feel free to move this comment where appropriate an keep on the good work.

I' using tw 1.8 now. The same problem shows up (and the same solution applies).