Here I am working on two instances of drupal. One that is lighter (with out any additional modules) for development and test. The other instance is a fully working site that I am maintaining. The notable different between these two instances is.
For 1st instance: I can browser and view files (like css/js) in browser those are located under /sites/themes/ and /sites/modules/*/theme/
For 2nd instance:
I view a fully rendered 'page not found' message upon accessing any css/js file.
and resultantly...
any file (css/js) linked to page.tpl.php fetches a "page not found"
How to deal with this issue?