Site Misbehaving After Editing A File

[need_help]

I have had my site running perfectly for a long time now but today i did something and not only to my main site but whatever i did was done to a test site i use for testing new add ons.

Site is fine until i log in or add a product to the basket.

I then get the site collapsing in on itself with nothing but the following text showing on the page.

1054 Unknown column 'p.products_price_w' in 'field list'
in:
[select p.products_id, p.master_categories_id, p.products_status, pd.products_name, p.products_model, p.products_image, p.products_price, p.products_price_w, p.products_weight, p.products_tax_class_id, p.products_quantity_order_min, p.products_quantity_order_units, p.product_is_free, p.products_priced_by_attribute, p.products_discount_type, p.products_discount_type_from from products p, products_description pd where p.products_id = '1' and pd.products_id = p.products_id and pd.language_id = '1']

Now i was editing a few files but i replaced them with the original copies after getting the above error. I cannot think what i have done so i wonder if anyone else knows where to look for the above sort of errors ?

In the meantime i am running a backup to re-install everything as it was from last night.

It would be nice to know what file is causing this for future reference in case i try editing the file again or run across it again. It might also help others if they do the same thing as i did.

Help appreciated.

[need_help]

Fixed this by replacing the yourstore/includes/classes/shopping_cart.php file.

I believe i swapped that over to a new one - Issue came about because i was editing the file for one of the recommended bug fixes but i was editing the file for a new store which was using the dual pricing add on and i stupidly just downloaded that file and uploaded it to my old store to save time with the bug fix changes.

Obviously the dual pricing module isn't installed in my old store so it sent everything haywire.

So silly me but thats the fix for me and i will check that no other files were affected by the dual pricing module and next time i won't be so lazy.