The same web project behaves differently under Framework 2.0 and Framework 4.0. When the ItemInserting event fires, e.Values is empty when the site runs on IIS with Framework 2.0.
When the ItemInserting event fires with the site hosted in VS 2010 using Framework 4, then e.Values is perfect.
Ha ha this sounds sort of familiar as I've just battled with this too.
There used to be a bug in the InsertItemTemplate for the ListView control and as I read somewhere it couldn't be fixed for "performance issues" but would be addressed in the future. This bug existed in ASP.Net 3.5 too I think.
If this is the same issue you are seeing, then it's a known problem. I guess Microsoft finally fixed it in ASP.Net 4.0 hence its now working.
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