Product listing URLs "not found"

[guybr]

After working hard on uploading materials I took a moment to see how the appear to users via the front-end of VM, and I clicked on a few of the listings.

I was surprised to find that many are yielding me this message on the page that subsequently appears:

---
Not Found

The requested URL /the-virtuemart-directory/home/123/2/product-category-name/product-name-detail was not found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

Apache Server at mysite.com Port 80
---

On the administrator's end, I do see the items listed and they are ticked to be published - any idea what's wrong??

I'm using VM 2.6.6 after having upgraded two times in the last 6 months. I'm using php 5.4...

[guybr]

I should point out: the items whose dedicated pages seem to be missing, do appear on the product listing pages with a thumbnail image, the title and description - as if everything is okay.

But for whatever reason, the product page itself doesn't come up...

[jenkinhill]

Looks like a strange url - turn off SEF to assist with debugging.

[guybr]

I disabled the "search engine friendly URLs" option and now the pages appear fine (thanks for the suggestion!)

But what does this mean?
And if I continue disabling the SEF will it really adversely affect my SEO?

[jenkinhill]

Are you using a third party SEF extension?