Subscription problems

I hav quite a few members that have signed up for recurring payments using the subscription payment system linked with PayPal.

Occasionally but not all the time, a payment that has been made thorugh this subscription is made but does not transfer through to their profile.

Ever since I have been getting payments I seem to get automated responses say the following:

Fraud attempt was detected in SITE NAME checkout system.
Here is details:
Date/time: Wednesday 21st 2009f October 2009 03:31:09 AM
IP: 67.99.08.45
Payment module name: paypal
Message: Custom check failed

This message always coincides with a subscription payment so it is not a fraud attempt at. It's strange because sometimes the subscription goes through fine but sometimes it doesn't.

Any ideas?

It turns out that there is a mod that can fix this though it does other stuff I don't really want not to mention that it costs $50 too.

I am told by Boonex that this is a major flaw in the software. What I have trouble understanding is if there is a mod out there that can fix it then why haven't Boonex released a patch?

Has anyone found a solution to this recurring payment problem?

Basically the first payment seems to go through just fine but subsequent payments after that don't, even though they do get charged by Paypal.

Any help would be much appreciated.