I have created and published successfully with shopping cart creator pro. I now purchased Shopping Cart Designer pro. I have created several templates, but everytime I go to export them to shopping cart creator, I get a message box that says my files are corrupted and it can't be done. Also when I click on the export button it always says the file with sct file already exists and do I want to override it. Shouldn't it be saving it in an scc file? Any help appreciated.

I would suggest is that you report this to CC rather than just here on the forums. Although the staff of CC does peruse the forums, it's not guaranteed that they will see every post that is attempting to report a bug. Always best to put in a support topic to make sure they get the information and can confirm the bug or help you work out what's possibly wrong on your end. Good luck on it.