Problem during migration from 12.2 to 14.0 sp4

I am facing error 404 not found issue during migration of library files from 12.2 to 14.0.

I am executing the html file from 14.0 workbench, but it throws error 404. But,on manually recreating the same file at the same location, the page is executed.

However, the next problem is when an external file is being referred to; the same problem occurs with object not found error.(example; for a flexigrid object creation, it does not find the jquery file which is present. On recreation of the external file, this error vanishes.)

So, the problem is that, it is required to recreate every file even after they have been imported.

Request your help in resolving the same.

Thanks in advance,

Rajee Vuta