Hi,
Since yesterday some of my virtuemart link stopped working and just shop a page with 404 on it, but not the custom 404 page I created.
this is an example www.wonderbaby.ro/la-masa/scaune-servit-masa.html
This appears to be randomly, there are categories, sub-categories and product page that have this problem, but not all of them.
Also the joomsef admin says Fatal error: Maximum execution time of 10 seconds exceeded in /home/wonder/public_html/administrator/components/com_sef/models/sefurls.php on line 62 when I try to manage sef urls.
also when i enter joomsef configuration i have the following error:
Warning: implode() [function.implode]: Invalid arguments passed in /home/wonder/public_html/administrator/components/com_sef/models/config.php on line 176

I am using Version: 3.7.4 and virtuemart extention 2.0.32

also search returns a 404 page so i decided to turn off sef for search.

Thanks

Please, try to delete 404 pages from cache and check if new ones are ok.
Maybe also some problem with hosting because script should not run more than 10 sec