[PrestaShop] Fatal error in module Upgrade-1.5: Using $this when not in object context

[amitj19]

Hey, My name is amit, i have upgrade my prestashop 1.5.4.0 to 1.5.5.0. than the website is running perfectly but in backend admin panel modules are not loading. when i click on modules link than there is showing a error on the page.. the error is like this..  

 

[PrestaShop] Fatal error in module Upgrade-1.5:

Using $this when not in object context

 

Please help me. i need to add some other modules in my shop.

Thanks,

Amit.

[vekia]

duplicated: http://www.prestashop.com/forums/topic/275424-prestashop-fatal-error-in-module-upgrade-15-using-this-when-not-in-object-context