Kim's right -- those restrictions DO exist on some hosting accounts where hosts have to be over-conscious of security issues due to the types of customers they have or due to frequent hack-attempts. Both of these reasons are GOOD reasons for you to MOVE somewhere else. If your host is a high target for hackers, you don't want your store on their servers. Period.
Further, as Kim mentioned, there are many good hosts which work very well with Zen Cart, in our Recommended Hosts section.
As to the errors you're getting, I suspect there's a problem with your /admin/includes/configure.php ... and that perhaps there are blank paths in there which should be set with more detail.
Can you please post the contents of your configure.php files without passwords?



