My question would be is where are you getting that url in our program. Your cat variable is set to some non numeric identifier in that specific url which is the issue and I do not see how you would be getting that link in the program anywhere.
If I remove that in the url then the seo urls correctly work.
its something to do with member galleries.... I have those disabled on AutoTalk.com and do not have the same problem there. I disabled member galleries at defencetalk.com and now you do not see the images when going to that url.
What I have said though is the cat variable in our program is typecast as an integer and that is what we pass in a url.
I do not beleive our program is outputting a url with the cat variable set to archive. I do not find anything like that in either site you have.
This whole thing is about some google link. We have no control over google content here. If I can find our program actually outputting the cat variable in a url as archive not a number then I can say this is an issue with our program.
Right now I am thinking as I noted above that a google bot is playing around with url content.
Your issue is this. On the one domain you used SEO urls.
Somehow in google you have some weird url that neither of us see the actual program making. You have in the urls cat=archive which is the issue. Cat variables are numeric and we grab the catname from that numeric identifier and use that in the SEO url. Your catname is empty in your links because your cat variable is wrong.