add image / add discount error

When I try to add discount or image or attribute in product listing nothing pops up and I get these types of errors. Any clue???

Changed website name to mywebsite.com


Webpage error details

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; InfoPath.2; .NET CLR 1.1.4322)
Timestamp: Thu, 23 Feb 2012 22:39:10 UTC


Message: Object expected
Line: 563
Char: 1
Code: 0
URI: http://www.mywebsite.com/admin/index.ph ... duct_id=51