Issues of making screenshots in OMAP

I am using the PVRshell inside the graphic SDK. The OpenGL ES is what I need for 3D visualization.  I installed Ubuntu on my PC (through VMware player) and use minicom to communicate with OMAP console.  I started from the Training course. After I built the training course and the program is running well on the OMAP. However, I use the keyboard to make screenshot by pushing the button "S". I found that the content in the screenshot is shifting horizontally. Just like the images I attached. Looks to me the screen buffer has been modified. Did anyone of you have the similar results? Is this a bug of the PVR shell?

Here is the system configuration

The training course I built is training course -5 05_BasicTnL
The OMAP system I am using is OMAP 3530
Thank you


for more details and the screen shots I made, please refer to the following link