How do I set parameters to only two decimal places on marketplace?

I am having trouble getting this working. It is giving me a PE104 error.
Please see below my correspondence with 2checkout:

Thank you for contacting My apologies for any delay in response regarding this issue, and I will be happy to help.

The following query string was captured during a test sale from your site:

The issue causing the PE104 error is the "total" parameter's value:


The value must only go to the hundredths place (2 decimal places) for our system to accept the charge. Once your cart passes in a correctly-formatted total, this will resolve the PE104 error.

Many thanks,