lucy24 - 6:46 am on Jun 27, 2013 (gmt 0)
... and that's why they keep telling you to use example dot com in posts. Not "mydomain" or "somesite" or anything else. Only "example" will do.
I find it simpler to leave off the protocol-plus-domain when I'm testing locally (MAMP in my case). Just use a leading slash. Nobody but you is in there, so you don't have to worry about path injections or malformed domain names or any of the other stuff you normally have to guard against.
Edit after looking at de-obfuscated URLs:
Your redirect seems to be doing exactly what you've told it to do. Request A, redirect to B. That means the problem is somewhere else.
Crystal ball says you have half of the redirect-to-rewrite two-step but you are missing the other half.
An URL ending in "Master-Product-Key" with no extension is obviously not a physical file. So further along in the htaccess you need a rule that rewrites the request to serve content from wherever it really lives. If you don't have this part, the server will look for "Master-Product-Key" and will come up empty-handed. That's your 404.