rewrite rule for file paths

Hi

We have migrated a site from Drupal 6 to Drupal 7 - from one apache server to another (old live to staging) - and many of the files (image files) have already been encoded twice %20 to %2520. Now transferring to our new live server nginx is not able to read/interpret the files. It seems to handle files that have come across as %20 but not files with %2520 %25 etc.

Is there a rewrite rule i can add to resolve this issue?

Ed.