There appears to be a bug in your regex.
When I test it against the following:
If you want to match both testnet AND bitcoin addresses, you could try:
/^[123mn][1-9A-HJ-NP-Za-km-z]{26,35}/
Note that these REGEX that I've supplied should match all the addresses indicated, but they will also match some strings that are NOT valid addresses. If you really want to be certain that you are finding actual addresses, you'll need to verify the checksum.
This did the trick for me... Agreed on checksum too. Although, I can rely on the validateaddress api call to bitcoind as well. Mainly, I wanted the regex to keep people from spamming a bitcoin address in chat.
Much appreciated for your help sir!