When trying to run the simple MMJFS test, one sometimes encounters an ``Unknown CA'' error. First thing to do is to make sure that your proxy is validating. Try: grid-proxy-init -verify -debug. This will let you know if you have a valid proxy. The debug information identifies where the trusted CA directory is located that is being used. If your proxy certificate isn't valid, it is likely (at least in my experience) that this is a cog.properties setting issue. Add/modify the following line in your cog.properties file: cacert=$HOME/.globus/certificates, except replace $HOME with your home directory. Create a symlink called certificates in your .globus directory that points to your trusted CA directory (alternatively you could copy all your trusted CA certs into your own directory, but then you have to maintain this directory). Hopefully now you can get a valid grid proxy.
Once you have this part working, then follow the steps in Section 1.3.1 to clean up the UHE's. Then try again. In my experience, these steps are sufficient.