DJ Egg - thank you for the quick reply. For some reason I didn't get an email notice but just happened to check back here. First, I didn't think about the Essentials Pack as being non-standard as it is named 'Essential' (my bad).
Secondly (also my bad), I totally forgot about having downloaded a Skin deleter (gen_sdel.dll) quite some time ago.
And, finally (your good and you're good), I got rid of it and it fixed the problem.
So ... thank you very much!