I am running Aptana Studio 3, build: 3.0.4.201108101506.
When I run "Check for updates" I get the following error
"A Problem occurred" 
 No repository found at file:/C:/Users/Keith/AppData/Local/Aptana%20Studio%203/plugins/com.python.pydev_2.2.1.2011073123/.
Any help would be appreciated
Looks like that filepath is set up as an update site in your preferences. I'd just remove it, since it looks invalid (maybe you installed a pydev zip from here?). Go to Preferences > Install/Update > Available Software Sites and then remove the entry for it.
error when running "Check for updates"