errror message at checkout

Hi,
I am still setting up my zencart. I have it working, I think, up until I go to my last confirmation in Paypal. If I place an order, it takes me all the way through. Whe I am asked to confirm my payment, this error message pops up:

Warning: reset(): Passed variable is not an array or object in /home/content/b/a/l/ballandskein/html/zencart/includes/modules/order_total/ot_tax.php on line 38

Warning: Variable passed to each() is not an array or object in /home/content/b/a/l/ballandskein/html/zencart/includes/modules/order_total/ot_tax.php on line 39

Warning: Cannot modify header information - headers already sent by (output started at /home/content/b/a/l/ballandskein/html/zencart/includes/modules/order_total/ot_tax.php:38) in /home/content/b/a/l/ballandskein/html/zencart/includes/functions/functions_general.php on line 44

I have checked the items as non taxable. As it is only an online business I think that is the way to do it. Please adviseme.
Thanks,
Judy

You might peek at this thread:
http://www.zen-cart.com/forum/showthread.php?t=64407&highlight=ot_tax.php+line

Then peek at this thread on Zen Cart v1.3.7.1 ...
http://www.zen-cart.com/forum/showthread.php?t=69769

I am at a loss here, please pardon my ignorance. How do I remove the modules and reinstall them with the patch. I have down loaded it. I see that there are a number of files in it that must be changed. Do I do each one individually overwriting as I go?
Thanks

Go to your Zen Cart Admin and to the Modules ... Order Total ...

Click on the Module(s) you need to remove and click the Remove button ...

The load all of the files from the upgrade ... and after those are loaded, you can Install them again fresh ...

Thanks. I am more confused than ever. The error is in regards to this module:
modules/order_total/ot_tax.php

I see that I can remove the "order-total" . However, the patch, when I looked at what was in it is all Paypal related and doesn't contain anything with that label. How would I reload it? Also, where do I load the patch? Do I remove the entire Paypal module?

Thanks again.

I just decided to go for it, used Filezilla and kept over writing things. It seems to have worked. Thanks. If that isn't the way I should have done it, I would still like advice, I know that I don't know what can get me into trouble.
Thanks again.