SEO ON causes an Internal server error 500

[Glock]

If I select SEO ON it causes an Internal server error 500, however, if I do leave if OFF my page navigation (1,2,3 END) does not work.

Instead of taking you to the next page, it takes you to the product category page.
If I select SEO to off, it works perfectly! If I select it to 'on' I get bad Internal Server Error 500 messages.

Does anyone have a suggestion?
I've disabled a lot of plugins that weren't necessary but still it continues.. and it seems to happen on only one page.

Anyway, I appreciate any help anyone could offer.

Many thanks
I am using version 2.0.18a
Joomla 2.5.9
and I don't want to post the URL so here's a tiny url for you
http://tinyurl.com/cqkjplc
it only happens on this ONE page, in summary;
SEO - DISABLED, I get the page working but the navigation-  1,2,3 END stops working
SEO - ENABLED, I get Internal Server Error 500

I appreciate any help as I've googled everywhere, came across only one topic regarding it;
http://forum.joomla.org/viewtopic.php?p=2188030

I cannot find any more info, so I would be very grateful

[Glock]

It's ok I fixed it!

For those who may encounter this error here is the issue;

On the products settings in shopfront, I allowed upto 20 items per page.
When I enable SEO, the page 'crashes' as it cannot cope with loading the amount of data - yes, shared hosting! (not mine this is a client) D'oh!

So, to solve it I did the following;
Conponent VirtueMart -> Configuration -> Shopfront -> Max products per view in frontend: 12
SEO disabled UNTICKED - no.
This enables the page number issue 1,2,3 end etc as they weren't going to the next page, only category view, but also stops 'Internal Server Error' on this page.

Problem is, IMO, any resource heavy page you have that triggers 'Internal Server Error 500' on shared hosting - needs to be looked at what you are loading.
If it's thumbs (which I cannot generate on this site) that cause it, limit the amount from 100 to 50 or less

if your products are 20-30-40 + and causing it, reduce it in increments

it worked for me..

Now, how do I enable thumbs (on the site not VM) without crashing... 

Good luck and sorry to waste anyone's time if anyone did look into it.

[Glock]

........

I lied, it's back.

Anyone have an idea please?

[Glock]

The only reason this has happened is because when I click page 1,2 or 3 on the product page, it taks you NOT to the next product page but to a category page and that's also messed up.
So if someone knows a way to fix the next page issue without the SEO enabled please let me know.

If not I have to figure out what to do to have SEO enabled but without it giving me an Internal Error
I realise I have bumped my own thread here and I apologise for that, just trying to share this and see if someone knows what the issue may be.

[jjk]

If you enable 'Debug System' in Joomla, which Information about your internal server error does it display?
Do you use any third party SEF extension?

Also you could use the Firefox browser plugin 'Firebug' to check if you have a javascript conflict somewhere. See here: http://getfirebug.com/

At the url you provided, I don't see any category with a lot of products.
My own shop is hosted on a cheap shared server, too. But I have no problems with SEF urls or setting the number of products to display to higher numbers. Pagination always works in my case.