You can try running "caf start amagent" from the agent machine that you want the job to run on.
I find it handy to have Microsoft Process Explorer installed when troubleshooting asset jobs, when you run the above command you will see "amagentsvc.exe" kick off as a child process to "CAF.exe".
You will also see all the child processes for "amagentsvc.exe" that gets kicked off such as the "amsignscan.exe" which is for the software scan. Once the software scan runs you will usually see the Asset Job you created trying to run. Usually you can identify if there is a hung process that is preventing the asset job from running. Only one asset job can run at a time, if one is hung, it can hang up the rest that are waiting on this one to complete. Also the asset job requires some user interaction and never completes until the user interacts with it. I have also seen in some cases, too many Asset Job checks were kicked off by continuing to request an Asset Job check over and over and then multiple amagentsvc.exe processes get started and hang. You also want to check the scheduling on the asset job to make sure its not set to only run once, or only run at certain times.
http://technet.microsoft.com/en-us/sysinternals/bb896653
Hope this helps!
-Chris