My 8gb 2" mp4 player doesn't work, it loops back to the menue when ever i try to go onto music or video, so i want to upload a fresh firmware, so i need the 9.1.51 firmware, thanks.

fredrico , it is never advisable to update any firmwares, as firmwares for these players are hardware specific, and varies greatly between players. Even if you found a firmware with an exact version and exact player casing, chances are 99% you would brick it instead.

i would suggest that you format your player first using MP3 Utilities Disk Tools, guide here http://www.mympxplayer.org/how-to-removing-memory-hack-vt2400.html
It seems very likely that your player has been hacked, as there is currently no evidence of legit 8GB players.
Also, the memory hack is likely the problem that you are encountering.