Formatting Chart Axis Labels in Word 2007

Hi,

I've created several charts in Word 2007, and I'm only having formatting trouble with two of them. In these, the horizontal axis labels keep displaying over top of each other instead of the text wrapping around like it does in the other charts. I've tried playing with the formatting options, but nothing seems to work. There is an option to "autofit" contents, but it's grayed out. I tried creating the chart directly in Excel, and I'm still having the same problem. Any suggestions?

Thanks!