Thanks for your quick reply Joe!
The skin installs fine - it just cannot be applied!
I just installed a clean version of 5.00.01 just to ensure I had not corrupted something locally - and I still get the same error.
"server tag is not well formed"
Then, if I keep trying it I get a solpartmenuprovider error for some reason. I wondered if somehow these two errors were connected. As I look at my skin file (html) i can not find any unclosed tags, spaces, etc - but that maybe an expert would/could see something I was missing.
Thanks again!