Folder Action Trigger Conditions

Hi,

I have a folder action which I need to be activated upon the arrival of a file within a folder. This works very well if I add the file through finder, or copy or move it in the terminal.

It doesn't seem to work if the file is created in the folder via a perl script which downloads some files. The folder action is never triggered for these files. The perl script is beyond my ability to comprehend and edit, hence wanting to use a folder action to finish it off!

Any pointers?

Thanks