>BTW, is it correct "I'm using the Mark McCasland's CA Builder", e.g. should I put a 'the' article in this context?

The following are correct:

I'm using Mark McCasland's CA Builder. (include the possessive - 's - remove the article)

I'm using the Mark McCasland CA Builder. (remove the possessive, add the article)

I'm using the CA Builder by Mark McCasland.