When you say the "Seperated" connector is on the card do you mean the Middle connector on the ATA66 cable? If so ... that IS your problem. The BLUE connector must go to the Promise card because wire 40 is severed on that connection only. That is how the Mobo identifies the cable as ATA66 compatible. Most ATA66 cables have a Blue connector, a Gray (Middle) connector, and a Black (End/Primary Drive) connector.
Also, the Promise ATA100 drivers are backwards compatible for ATA66. The BIOS is not.