When formatting a file, Aptana reports:
Unable to format. See error log for details.
I haven\'t been able to find the error log.
!ENTRY com.aptana.formatter.epl 4 0 2012-12-07 09:47:47.868
!MESSAGE (Build 3.2.2.201208201020) [ERROR] com.aptana.formatter.epl/debug Error while formatting the code in your editor.
Please submit a bug report through Studio's support and include the relevant code which triggered this error.
You may also turn on the com.aptana.formatter.epl/debug at the Studio's Troubleshooting preference page to log more details about this error.
According to the docs it should be in the current workspace /.metadata/.log
https://wiki.appcelerator.org/display/tis/Accessing+the+Log+File
You could access it via Help > Aptana > View Log File.
use the installation to repair it.
Run installation > Chose Repair > Done