issue with marketpress paypal express - although I changed to 10000

Dear wpmudev,

I already read many support posts and I already changed in the paypal-express.php the number from 60 to 10000. I changed it and I added it with the original script. Unfortunately, nothing changed. I still receive the error message. Pls have a look at the attached pic.
Pls let me know what I can do bc some customers are interested in my services.
Well, the payment goes through but the error message appears and thats quite confusing.
The issue has been discussed a couple of times here on wpmudev but I still dont get it to work.
Pls let me know
(will upload the pic in the next post)
thank you very much
with best regards
R.