SharePoint: Resolving Web Parts Appearing as ErrorWebPart while enumerating them

Issue:
ErrorWebPart
"File not found"

Description:
After working on this issue for about One month, I found a wonderful Post by Sandeep SharePoint: All Webparts appear as ErrorWebParts when using SPLimitedWebPartManager.

Resolution:
So here is what is required to be done
1. Provide Context (see Sandeep Blog)
even if this doesn't work then
2. Make sure you custom webpart library (.dll) is either GAC'ed or you add it as reference to the application from which you are trying to read the web parts (note: if you are adding reference make sure it is the latest one).

Happy programming!