Belkin Wireless MAC OS X Connect Problem

I have a Belkin wireless router, that is encrypted, but my iMac (MAC OS X) will not recognize the encryption key. It picks up the signal, but when I try to key the encryption key/passphrase, it won't give me access.

According to Belkin, I have to use the 64bit manual encryption process to get my Mac to recognize the key, not the passphrase.

Anyone have any ideas?

Thanks