Hi Marcel,
Thanks for your request.
Please clarify: what version of BCC compiler are you using?
I assume it's BCC version 5.5, but your minigui library was built using BCC 5.8.
You have 2 options to solve this problem:
1) replace your outdated BCC with version 5.8
2) rebuilt your minigui library with your BCC 5.5 compiler
Hope this is helpful.
Regards,
Grigory