Commented Issue: SchemaUpdater invalid Cast [10823]

I always get an invalid cast exeption when i try to create schemaUpdater from my WP DataContext class!

I tried to remove like some suggestions in WWW.
public System.Data.Linq.Table @__VERSIONs
{
get
{
return this.GetTable();
}
}

but no chance!
Comments: ** Comment from web user: ErikEJ **

I mean I need a solution/project that in can compile and see the source code, that causes the error