Hello,
okay, it took some time to find out what causes the issue in your project. It's caused by your Line 302 (see attached screenshot). Why do you remove this BACKUP folder?
Our debugging process found out that you install several files multiple times. For example:
Infragistics4.Documents.Core.v19.1.dll
Infragistics4.Documents.Excel.v19.1.dll
Infragistics4.Documents.IO.v19.1.dll
… and more ...
Installing the same file multiple times creates backup copies in the BACKUP folder. The main problem here is that you remove the backup folder after your installation.
To fix your problem:
1. Do not install the same files multiple times (I think it's caused by our wildcards *.*)
2. Do not remove the BACKUP folder
And as a side note, the registry manipulation in lines 210 and 211 is not allowed in Windows. Please remove the "Wow6432Node" entries.
Does this help? After you have fixed this, your install and uninstall should work again as expected.
Friedrich