Paypal Things Don't Appear to be working at the moment error.

I am using Open Cart 1.5.5.1 with the Paypal Standard payment module and since some recent changes with Paypal when customer adds an item/items to their cart with many options it causes the error "Things don't appear to be working at the moment . Please try again later." If I remove the items that have a lot of options from the cart and try again checkout goes through as it should so it is most definitely option related.

After some searching I found this from Paypal:

Passing currency symbols ("$", "£", etc.) or values other than integers (1, 2, 3, etc.) and decimal points (“.”) in the amount field. For example, "1234.50" is correct, but "$1,234.50" isn't allowed.
Passing country code values greater than two letters. For example, "FR" is correct, but "France" or "fr_FR" isn't allowed.
Passing more than 127 characters in the item_number field. For example, don't use the item_number field for "Note to Buyer" information.
Passing more than 64 characters in the option fields (on0, on1, etc.).
Passing duplicate empty parameters.
Passing address_override=1 without passing an address.

I am assuming the info highlighted is the cause. Does any one know of a solution? Seems we need a fix for the Paypal Standard payment module for 1.5+

I am getting this error just now too,

I have checked my post to Paypal and everything in the points you found are all fine.

Seams to be working now, havent made any changes here so must have been an issue at PayPals side

This has just happened to me too. I phoned Paypal and they directed me to a help page which says:
"If you use third-party shopping cart software, such as a hosted shopping cart or software that you installed on your web server, the developer of that software may need to correct a problem in their code. Contact your cart provider directly and have them review this guide."
Here is the link to the guide on Paypal:
https://www.paypal-techsupport.com/
Click on the first question:
"My Payments Standard integration isn't processing transactions. What should I do?"
Unfortunately, the answer is not much help as it needs to be done by Opencart as the payment system is integrated. If anyone knows how to manually correct this error, that would be great.
(The other two answers are for buttons, and for hand coding HTML)

Can anyone help?

Here is a most recent reply from Paypal:

Your shopping cart is passing a few duplicate parameter names in the payment request sent to PayPal, and whenever there are duplicate parameter names, this causes problems. I have listed the full parameters from my test below, and have bolded the duplicate parameters that will need to be updated to increment the suffix from 1 to 2, e.g. "item_name_2, item_number_2, amount_2, quantity_2, weight_2

Does this make any sense to anyone that can point me in the direction to fix it?

I am not sure why no one has a solid fix for this yet but regardless here is a bandaid method that may help some of you for now. I edited the pp_standard.tpl file in my theme (or edit in the default theme folder if you don't have this file in your theme folder). I removed lines 17 & 18. And my site is allowing orders to pass through to Paypal now. I haven't went further to see the result when it passes back to my order info in my store but at least orders can be placed now.

<input type="hidden" name="on<?php echo $j; ?>_<?php echo $i; ?>" value="<?php echo $option['name']; ?>" />
<input type="hidden" name="os<?php echo $j; ?>_<?php echo $i; ?>" value="<?php echo $option['value']; ?>" />