Credit Card not accepted

[Ousel]

I have set up my cart to accept credit cards and debit cards.

I have successfully received a payment by Visa card, and have put through a dummy transaction with my debit card.

BUT I cannot process my own credit card!

I have a Mastercard, and after entering the details I an sent back to checkout step 2 with the message:

"The credit card number starting with was not entered correctly, or we do not accept that kind of card. Please try again or use another credit card.[cc]"

I have 2 questions.

1) Why can I not process my Mastercard?

2) In the error message received, the start of the credit card number is not shown. Why not?

[DrByte]

1. Admin->Configuration->Credit Cards ... is Mastercard enabled?
2. Which payment modules do you have enabled? Admin->Modules->Payment
3. What version of Zen Cart are you using?
4. What addons have you installed?
5. What browser are you testing with?
6. Who is your hosting company?

[Ousel]

1. Admin->Configuration->Credit Cards ... is Mastercard enabled?
Yes

2. Which payment modules do you have enabled? Admin->Modules->Payment
Credit Card
Paypal IPN
UK Debit & Credit Card

3. What version of Zen Cart are you using?
Zen Cart 1.3.0.2
Database Patch Level: 1.3.0.2

4. What addons have you installed?
uk cc 1.3.0.1 mod.zip by Kelvyn

5. What browser are you testing with?
Internet Explorer v6.0.2900.2180

6. Who is your hosting company?
Eclipse
www.eclipse.net.uk

[stagebrace]

Do you have MasterCard enabled?
Goto Admin>Configuration>Credit Cards
Make sure MasterCard has a value of "1".

[Ousel]

Yes, Mastercard is enabled.

[Ousel]

I haven't heard back on this one for nearly a month. Does that mean that no-one knows the solution?