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 web site as a guide: http://www.theartofsharepoint.com/2007/05/how-to-build-solution-pack-wsp.html
I get this error in the log files:
09/23/2008 14:13:03.67 w3wp.exe (0x1B5C) 0x1534 Windows SharePoint Services Web Parts 8l4d Monitorable Error importing WebPart. Cannot import Project Filter.
09/23/2008 14:13:03.67 w3wp.exe (0x1B5C) 0x1534 Windows SharePoint Services Web Parts 89ku High Failed to add webpart http%253A%252F%252Fuk64p12%252FPWA%252F%255Fcatalogs%252Fwp%252FProjectFilter%252Ewebpart;Project%2520Filter. Exception Microsoft.SharePoint.WebPartPages.WebPartPageUserException: Cannot import Project Filter. 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(...
09/23/2008 14:13:03.67* w3wp.exe (0x1B5C) 0x1534 Windows SharePoint Services Web Parts 89ku High ...String eventArgument)
The pertinent bit is:
http%253A%252F%252Fuk64p12%252FPWA%252F%255Fcatalogs%252Fwp%252FProjectFilter%252Ewebpart;Project%2520Filter.
Exception Microsoft.SharePoint.WebPartPages.WebPartPageUserException: Cannot import Project Filter.
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)
And that's accompanied by a rather terse error message: "Cannot import web part".
I have checked and my .dll is registered as safe, it is in the GAC, the feature is activated, and the web parts appear in the web part library with all of the correct properties showing that the webpart files were read successfully.
Everything appears to be in place, yet I get that error and little explanation from SharePoint of how to resolve it.
Any help finding a solution is appreciated.