Will have to take a look.
Edit: Is it possible that this entity is static, instead of dynamic.
If you put the mouse over it and it turns red, then it is static. Objects must by dynamic for scripts to function ion them.
Edit2:
Try assigning your script to the acid barrel in the barrels folders. See if it works there.
Also make sure that the name of the script and the function names are exactly the same.
The script does run on my machine and destroys the object assigned to it.
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 2400 Mhz, 4 Core(s), 4 Logical Processor(s), 8gb RAM, Nvidia gtx660, Windows 7 Pro 64bit