I was working on a tutorial today, for the mirror modifier.  I was going to delete some faces, for do clipping.  I went to switch it to face mode, and got this error:

I'm a little confused but, i thought multiers were multable modifiers.  Anyway, how do you disable multiers?
After a while, getting frustrated with this.  I started a new document.  When I went and put a material on the object.
I came across this:

Does anybody know what is going on? Do I have a bug or something?

If you saved the file you were working on simply open it and click the Apply Multires button under the Multires tab. Since you don't have any multires levels active in the model this will clear the error msg without causing any actual change to your mesh allowing you to proceed with editing.

The problem on the new file you created appears to be a video issue, google for information related to problems between your video card and Blender to determine if this is an ongoing problem with a solution or just a hiccup in the flow that may or may not repeat itself. I had a couple of oddities show up with Blender 2.48 on my Nvidia 280GTX card that were resolved either with the 2.48a release or the update to my video drivers, unsure which as I did both updates at the same time.

Thank you, I believe I see how this works now. 
Thank you for enlightening me on the video card.  I have had this problem before with other applications.  It has something to do with alphas and transparencies. 
I did find a workaround.  Basically, in the button window.  There are tabs on top of tabs. So what I did was: rearrange the tabs, and saved it as my default user interface.

I have a PCI express 7200 GS, nVIDA EVGA.  If I update Blender, it would probably fix this.  I understand that there are a lot of bug fixes in the 2.48a release.
 Again, thank you for your help.  Very much appreciated!