InfoPath Dev

I did that. But still the same thing. Previously I used to be able to open the visual studio tools, by navigating to Tools->Programming->Microsoft visual studio tools. But now, when I try to do that I get the same error.

We are developing an infopath form which is pretty big. We have around 38 views and the code behind is around 3500 lines of code. When ever I try to open the code behind I get an error, "Infopath has encountered an error. The operation failed". I tried to remove the code behind and add it back. Still the same thing.

When I try to upload an Administrator Approved form template I get the following error. Object reference not set to an instance of an object.   at Microsoft.Office.InfoPath.Server.Util.FeatureGenerator.FeatureNameByFeatureId(SPFarm farm, Guid existingFeatureId)    at ...

I am trying to upload an attachment to the sharepoint library using qrules. I dont see the doucment being uploaded to the sharepoint library. Herewith I am attaching the xsn file.