Download the UDisk Checker
It will tell you what type of Disk your player is (make sure you have your player plugged in before using the tool).
Reading from the post replies on s1mp3.org someone suggested you might have a Sigmatel board, which the Upgrade Tool won't work for. It will only work for ACTIONS boards.
Can you give me more information about your player?
If you use the s1fwx tool, can you extract the firmware from it?