My b2evolution Version: 2.4.1

Excerpt sent in trackbacks: test again
Sending trackback to: http://www.barnesnet.co.uk/htsrv/trackback.php?tb_id=49 [get]
Response: No valid trackback response. Maybe the given url is not a Trackback url. " Untitled Document Woops an error has occured. 500 Please click here to return to our homepage "
Sending trackback to: http://simonbarnes2007.spaces.live.com/blog/cns!D75E9E709223C907!145.trak [post]
Response: [Failed] Unknown Error

I have been trying to test the trackback feature of my site but get the above error. I tried two trackback urls that time but it is the same for one on its own. One is from my site and another from a live myspace.

Also inserting a trackback url from my site within a blog on myspace gets an error.

I think the problem is the error 500 page, I have posted about this problem previously where I cannot logout from my site without encountering an error unless I am on the home page.
http://forums.b2evolution.net/viewtopic.php?t=14830&highlight=

I have tried the ht.access additions etc but nothing helps.

Any ideas as this is obviously an issue that is affecting various parts of my sites features.