PayPal Express module disappeared?

Is it normal for this to happen?
I upgraded from 1.3.8 to 1.3.9h, all went smoothly. No problems at all until today when I received an email..

"10417 Transaction cannot complete. - The transaction cannot complete
successfully. Instruct the customer to use an alternative payment method. "

I've gone to check in my admin, and there are no Paypal modules installed at all anymore :(

Can anyone help?
Do I have to install one?
I'm completely stuck!

I do have my complete site and files backed up if there's anything I can restore from that, I just don't know what to restore if that's the case.

Thanks.

When you upgrade you should uninstall and reinstall any shipping and payment modules.

Hm the instructions didn't mention that, and they were pretty detailed.
My shipping module is still intact, it's just missing the Paypal payment modules.
All my Paypal files appear to be intact on the server, it's just not using them it seems.

Ok all fixed.
I also contacted my webhost support and they pointed me in the right direction.
Aaaages ago a deleted google checkout and all it's files as it was causing issues.
It seems that I left behind the shipping module associated with google checkout, which couldn't initialize as the files were not present - That caused Paypal and all the other payment modules not to work either.

Thanks for posting the solution to your mystery.

I'm having the same issue. I have removed and fixed all files associated with google checkout but it's still giving me issues. Any ideas?

I'm getting my site upgraded from 1.3.7 to 1.3.9 and the payment modules that I was using have disappeared from the admin. I've tried re-uploading them, but it's still not working. How do I fix this?

The page itself is allowing me to choose the missing payment modules. Confusing. Help please? I can't seem to find any information on this issue.

Thanks!

Ok I fixed it! Yay! I had to delete all the files in includes/modules/payment and then re-uploaded and they reappeared in modules/payments in the admin.