SharePoint error: “Cannot import Web Part”

Question

I have a web part that I\'ve developed, and if I manually install the web part it is fine.

However when I have packaged the web part following the instructions on this w

Answer 1

Solved mine.

i was getting this error:

===========================================================================
Error importing WebPart. Cannot import ........ Web Part.
Failed to add webpart 
Exception Microsoft.SharePoint.WebPartPages.WebPartPageUserException: Cannot import ... Web Part.     at Microsoft.SharePoint.WebPartPages.WebPartImporter.CreateWebPart(Boolean clearConnections)     at Microsoft.SharePoint.WebPartPages.WebPartImporter.Import(SPWebPartManager manager, XmlReader reader, Boolean clearConnections, Uri webPartPageUri, SPWeb spWeb)     at Microsoft.SharePoint.WebPartPages.WebPartImporter.Import(SPWebPartManager manager, XmlReader reader, Boolean clearConnections, SPWeb spWeb)     at Microsoft.SharePoint.WebPartPages.WebPartQuickAdd.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument)   
===========================================================================

"Cannot import webpart..."

The problem was: Non-matching GUIDS

Check if the guid on webpart class , and in the .xml and in .webpart class are same.

I was copy-pasting code from other webparts sources. ( Mutliple Document Upload Wepart on Codeplex) and forgot to fix guids.