vb 2010 unbalanced stack

[Niya]

The error you're getting about the type being exposed is a scope error as paul suggests. My guess is that you declared the TileRec structure as Friend and MapInfo as Public which would cause that error. Changing TileRec to a Public declaration would fix that problem.

Paul already told you how to fix the implicit conversion error.

EDIT

Actually, I just remembered that modules default to Friend access in VB.Net which means that anything declared in it cannot be exposed outside the assembly. Declare your module as Public.