Highrez

Possible to install without internet connection?

Should be possible but I havn't tested it recently.

However, you must make sure your Windows root certificates are up to date else you may have problems running XMBC after installation. XMBC runs as an accessibility tool, for which it needs to be digitally signed. Those signatures are updated (yearly) ad if your computer isn't up to date, it may not trust the signer - and in that case you'll get a weird error (something about a referral - a generic windows error message! It's covered in the FAQ and is fixable by applying a MSKB patch but its not obvious).

The installer does open a web page on install but that shouldn't stop it working if there is no internet. It just wont show the page - no big deal!

Any problems, then the portable version should work and does not need installation - although it has some limitations as it cant run as an accessibility tool - meaning it cant interact with higher privileged processes and thus will simply not work in some cases.

"you'll get a weird error (something about a referral - a generic windows error message! It's covered in the FAQ and is fixable by applying a MSKB patch but its not obvious)."

That's the issue sounds like. Good man.