Key commands don't work in certain programs.

It seems that some of my keyboard shortcuts don't work in Adobe CS5 programs. For example when I try to edit text, the Shift-Command-right bracket works for sizing the text up, but the Shift-Command-left bracket doesn't size the text down, as it should. I've read the forums for Adobe and it seems that people think it's a MAC issue not an Adobe issue. Any ideas why this might be happening?