Attempted to recreate problem but could not - I also removed some of the lowercasing but I don't believe it's the issue so have reversed those changes. I've posted on a few threads in dnnsoftware.com so we can get an accurate set of repro steps as I don't feel comfortable fixing something until we can verify why it's a bug.
Closed issue per Cathal's comments.
However, I feel we lack of detailed information from the original description of the problem, such as, which skin, how it was applied, which module added...
Close as it is till further information provided or probably already fixed indirectly.
sorry for the lack of information - this was because the exception happened in all cases of skins applied via admin->skins (and no modules were added)