Paypal issue with dripped content

Paypal is giving users the following error:

"Invalid second trial period. You must specify valid values for the A2, P2 and T2 parameters for a subscription."

I've seen this question asked before but there doesn't seem to be a solution for this problem.

My membership site is setup as follows:

Week 1 - finite, 1 week, £24.99
Week 2 - finite, 1 week, £0.00
Week 3 - finite, 1 week, £0.00
Week 4 - finite, 1 week, £0.00
Week 5 - finite, 1 week, £24.99
...

There are plans to continue adding content, so there will be a payment every 4 weeks, until we have no more content, when we'll have to add a 1 month serial level of £24.99

Is this something I can fix myself, or does it have to do with the plugin?