GTK application hangs in Windows and Wine, works fine in Linux

[admin houbysoft com]

Hi,
I've been trying to fix this myself but I had no luck so far, so I'm
asking here, I hope it's the right place to ask.

So here is my problem:
I developped a GTK application for converting encodings, it's open source
and the URL is here if you want to see the source code perhaps :
http://houbysoft.com/cc/
The problem with it is that it works completely fine on Linux, but if I
build it in Dev-C++ and try to run on Windows, just a blank window
appears, and it hangs, leaving me the sole option to force quit it.
I also tried running it in wine, gives this error:
err:ntdll:RtlpWaitForCriticalSection section 0x13b670 "?" wait timed out
in thread 003f, blocked by 0000, retrying (60 sec)

Also let me say that I wrote also other GTK applications so it's not a
problem with the compiler settings, etc., other GTK apps I wrote ran fine
so far in both OSes, with the same compilation procedure.

Thanks for your precious help!

Jan