apache - Handle multiple sublink depths with php with little or no mod rewrite dependency -

i trying write content management system , have hit snag while trying develop seo friendly urls. using php handle urls, have problem when try request_uri more 1 depth level. trying avoid using .htaccess handle this, because system easy set on iis/nginx/etc , not want apache dependent more necessary.

i have in htaccess file

fallbackresource index.php 

and in php have class handles request_uri slug checking see if record exists in mysql database. works fine if request like

http://example.com/foo 

however throws internal server error if request is

http://example.com/foo/bar 

this seems occur if have blank index.php, suspect answer must @ htaccess level. how can system handle multiple request_uri depth levels? need use mod rewrite regex or there less apache dependent solution?

my bad, needed change .htaccess rule from

fallbackresource index.php 

to

fallbackresource /index.php 

the missing slash causing error. -.-