I'm trying to install mathcad 14 on this system: Microsoft Windows XP Professional x64 Edition Version 2003 Service Pack 1. Computer: Intel Core Duo CPU E6750 @ 2.66GHz, 4.00GB of Ram. According to the official site it seems to be compatible with my hardware and software:
Seems your Mathcad version can't stand 64bits OS, but Mathcad 14 does, quoting from your link. Not sure there's a 32bits version and another 64, maybe you should ask the customer service, this is quite strange...