Can't create products, fatal error

General General Questions
1

My cs cart installation stopped working properly after some time.

I'm not able to create products mainly due to “add category” is bugged now.

Here is step by step guide:

  1. I create a product and enter the name
  2. Trying to chose category because product can't be saved withot one chosen.
  3. When I click “add categories” button, my browser warns me that you will be navigated away from the page.
  4. Then I see the list of categories but in a weird format text list.
  5. When I chose the categories and try to save, I get an error


    “Fatal error: Cannot use string offset as an array in /store/var/cache/templates/admin/%%E4^E42^E4252AD1%%mainbox.tpl.php on line 55”



    It worked fine for some time when I changed browser from Chrome to Firefox but now it doesn't work on all browsers.
2

Weird, it works fine from other PC. What could be the issue?

3

Clear cart and browser cache.

4

Sadly that didn't help. One more thing I noticed that product is being closed when I hit save. It should do that in save and close only if I recall right.