Jane

This has got nothing to do with Codecs or Apple. Its actually a Windows server 2003 issue.
If the FLV file is working locally but not on the server then the following should fix it - you need access to make changes to the servers IIS;

- open IIS on ther server
- right click on the server name
- click on properties
- click on MIME Types
- click New

add the following information: add (.flv) as the file extension and (flv-application/octet-stream) as the MIME Type.

Should work fine now...

Jay