can not login with SCLogin module

I want to follow the issue of this post as I can not reply there:
www.sourcecoast.com/forums/jfbconnect/jf...-with-sclogin-module

after a lot of testing, I found some clues about it.
when I successfully login with SCLogin module, cache files will be created in /public_html/cache/_system folder. after the these cache files created, SCLogin will become not working properly. so I disabled cacheing in SCLogin module setting, then the issue seems to be gone.