Decrypt Problem

I'm having a bit of a problem with the decryption of user passwords. Here is the error I'm getting:

"There has been an error while trying to encrypt or decrypt your input string: Given final block not properly padded. "

Here is the decrypt code:

<cfset dPassword = Decrypt("#qVerify.uPassword#",APPLICATION.Key,APPLICATION.pKey1,APPLICATION.pKey2)>

Any help would be appreciated.