renaming files in subfolders with bash

Folks-

I’m trying to rename files within a folder (and subfolders). This is pretty easy with AS but I’d like to get it to work as a shell script as it seems a bit faster in bash. The following script works with files in the top directory but whenever descending into subfolders it globs the subfolder name onto the file designation and fails:

the directories:

/Volumes/Design/JOBS/168,000-168,999/168004_FA_IRA_SIMPLE_App
/Volumes/Design/JOBS/168,000-168,999/168004_FA_IRA_SIMPLE_App/Final_Doc

the code:

do shell script "cd '/Volumes/Design/JOBS/168,000-168,999/168004_FA_IRA_SIMPLE_App'; for f in `find . -name '151811*.*'` ; do mv $f ${f/151811/168004}; done"

the error:

mv: ./ and ././ are identical
mv: rename Final_Doc/151811_fnl.pdf to Final_Doc/168004_fnl.pdf: No such file or directory
mv: ./ and ././ are identical
mv: rename Final_Doc/151811_pp.pdf to Final_Doc/168004_pp.pdf: No such file or directory
mv: ./ and ././ are identical
mv: rename Final_Doc/151811_FA_IRA_SIMPLE_App.indd to Final_Doc/168004_FA_IRA_SIMPLE_App.indd: No such file or directory
mv: ./ and ././ are identical
mv: rename Final_Doc/151811_wrt.pdf to Final_Doc/168004_wrt.pdf: No such file or directory

any help would be appreciated!

-Ralph