Edit template error
 

When i click the edit templates it does not load my page correctly and shows this error

Webpage error details
User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; InfoPath.2)
Timestamp: Sun, 28 Feb 2010 17:10:32 UTC

Message: 'document.forms.tform.tl2' is null or not an object
Line: 50
Char: 4
Code: 0
URI: http://www.back2bowlers.co.uk/forum/...fy&expandset=2


ANy Ideas what it might be??