Rachael w.

@ For the limit, find
products_description.products_name AS name, and change it to
LEFT(products_description.products_name, 150) AS name, The identifier code checks the Brand, GTIN and MPN columns. If two of those are empty, or not used, the identifier should be false.

You only show some of the settings so I can't say what the problem is. But, in case you didn't notice, for many of the options there is a main option that enables/disables an option (those are what you show). Below those are related options that have to be filled in. For example, you have the google product category option enabled but you have to enter what that category is in the related setting. Please take another look with that in mind and post again if it doesn't help. And, in that case, post all of the settings.

What Jack is saying is, your first define statement says:
 
define('OPTIONS_ENABLED', 0);
 
However, if you're using any of the options at all, that first define should say:
 
define('OPTIONS_ENABLED', 1);
 
So you enable the options, then tell the program specifically which ones you want to use...

I figured it out, edited the wrong file! Now that I have edited the CORRECT file it works perfectly! Thank you so much Rainer for your help and I apologize for my own stupidity. 

This addon will work with SEO 5 except for the option to change the url's via Header Tags SEO. If you don't want/need that option, then you don't need to change.

Try replacing all of the code in GenerateManufacturer2Sitemap with that in GenerateManufacturerSitemap and see if it works, which it should. If it does, then it is just a matter of swapping the lines until you find the problem.