vqadmin buffer overflow

I

I've isntalled last toaster packages from www.qmailtoaster.com on a 
Mandriva 2006 linux system.


[root@nex tmp]# rpm -qa | grep vqadmin
vqadmin-toaster-2.3.4-1.3.2mdk
[root@nex tmp]#


All works quite fine except this issue (grabbed from apache error log):

*** buffer overflow detected ***: 
/usr/share/toaster/cgi-bin/vqadmin/toaster.vqadmin terminated

This sometimes, not always, happens when I select from vqadmin ->list 
domains >$domain_name.
Sometimes it shows an empty page (also if I look at the source.. it's 
completely blank) sometimes it works correctly and I can see users, 
passwords and so on...

Note:

-it's not a url problem.
-it doesn't happen always, only on some spcific domains, and always on 
those.

How can I solve this?

many thanks.