age of mythology gold edition vs older version in multiplayer

Hi there my two sons wanted to play AOM titan against each other so brought a
gold edition. I already had the old two disc version. all installed on
computers but when they try multiplayer error message says. either the patch
or version are not the same. I have updated both softwares picked up the
patch from the website and still they won't accept each other as being
compatible. Help please otherwise I just wasted money on buying a second
edition of AOM, both computers are running XP