Hello, I have been struggling for four days now with a sharepoint webparts issue and did not manage to solve it.

I developed a personal webpart using chart fx charts for .Net. In order to test this webpart, I was using a test site.

The webpart works well, the graphs show correctly and I am absolutely sure everything is ok with the webpart. Once I was sure I could deploy it on the production site ( myserver:80 ),

I tried to do so using WSS extensions for VS (WSSeVS). There was no problem deploying the webpart and it appears in the webpart collection of the site. But, when trying to add it to a page or to preview it, I have got an error : 

Cannot import myWebPart Web Part. à Microsoft.SharePoint.WebPartPages.WebPartImporter.CreateWebPart(Boolean clearConnections) 

à Microsoft.SharePoint.WebPartPages.WebPartImporter.Import(SPWebPartManager manager, XmlReader reader, Boolean clearConnections, Uri webPartPageUri, SPWeb spWeb) 

à Microsoft.SharePoint.WebPartPages.WebPartPreview.get_WebPart() à Microsoft.SharePoint.WebPartPages.WebPartPreview.CreateChildControls() 

à System.Web.UI.Control.EnsureChildControls() à System.Web.UI.Control.PreRenderRecursiveInternal() 

à System.Web.UI.Control.PreRenderRecursiveInternal() à System.Web.UI.Control.PreRenderRecursiveInternal() 

à System.Web.UI.Control.PreRenderRecursiveInternal() à System.Web.UI.Control.PreRenderRecursiveInternal() 

à System.Web.UI.Control.PreRenderRecursiveInternal() à System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) 

Both sites are on the same server. The only difference is that my test site port was 40560 whereas main site's port is 80.

The webpart still works on the test site but whatever I try I do not manage to get it working on the main site.

I do not have any idea on how to solve it now. Hope you will be able to help me.

 Thanks a lot and have a good day.