I tried POE and threads. Even though they say something about it (http://poe.perl.org/?Poe_faq/is_poe_thread_safe) I have the impression, that POE is not thread-safe. win32 complains with an Attempt to free unreferenced scalar: SV 0x2afba80 during global destruction when I create a thread inside a session. The process continues. If it comes to a point, where this execution has to be triggered again, Perl aborts with an Application Error dialog - The instruction at bla bla referenced memory at bla bla. The memory could not be "read"..