If the original error you were seeing is that the package contains "invalid File Extensions." If so you simply need to use the "ignore file extensions" option in the install wizard. The multiple dnn file error is caused by recreating the install zip file.
Microsoft actually recommends including the debug symbols (.pdb) file with each release of your software. This is done for many reasons including helping to report errors in the software back to the vendor as well as allowing the customer to better understand the software if in fact they are developing code that interacts with it.
I will add the urls to the standard PayPal buttons in the next release. That is great feedback and I do appreciate it!
I apologize for the delay in response and am glad to hear that you were able to get it working. If you need to reinstall or install this module on a different portal please use the method stated above.
Thank you!