This is an unusual and annoying problem.
I'm running the latest version of Pymol on two PC machines, one in my office and one at home.  I cart my session file on a jump drive back and forth.  On my PC at home, the session file displays the labels just fine and dandy.  But using the same session file, the labels are not displayed on my PC in my office.  Same session file, recurring problem over several days.  Even when using the distance wizard, the dashed lines display for the distance, but the text (residue number and the distance) does not display in my office. 
Furthermore, this is not a problem with the machine, but with this session file.  I can load a different session file on my office PC and the labels display just like they always have and should.
Why, if I'm using the same session file on two different machines, will one display labels and the other machine does not?  Is there a setting parameter that I'm not aware of?
Marilyn D. Yoder
Division of Cell Biology and Biophysics
University of Missouri-Kansas City
5007 Rockhill Rd.
Kansas City, MO  64110-2499
phone: 816-235-1986
fax: 816-235-1503