DEP is a windows OS security protocol. At this time the DEP message is confined to the 6.4.3 update (and affects a small number of Vista users).  Since DEP provides an essential security service we can not advocate that DEP should be disabled. However, should you decide to disable DEP you can re-enable DEP again through almost the same procedure (a different command prompt is required). The choice is yours. Should you wish to disable DEP, please see the following instructions:

Disable DEP

1/ Click the Start Button.

2/ On the Start menu Click All Programs.

3/ On the All programs menu Click Accessories.

4/ From the Accessories menu Right Click on the Command Prompt and, from the drop down menu, Select Run as administrator.

5/ If the User Account Control feature pops up you will need to either press the Continue button or else provide UAC with the details it requires.

6/ When the Command Prompt window opens type: bcdedit.exe/set {current} nx AlwaysOff and press Enter.

7/ If all has gone well you should see a message saying that The operation completed Successfully.

8/ Close down the Command prompt window and Restart your PC for the changes to take effect.

Enable DEP

If, at a later time, you want to re-enable DEP proceed as follows:

1/ Click the Start Button.

2/ On the Start menu Click All Programs.

3/ On the All programs menu Click Accessories.

4/ From the Accessories menu Right Click on the Command Prompt and, from the drop down menu, Select Run as administrator.

5/ If the User Account Control feature pops up you will need to either press the Continue button or else provide UAC with the details it requires.

6/ When the Command Prompt window opens type: bcdedit.exe/set {current} nx AlwaysOn and press Enter.

7/ If all has gone well you should see a message saying that The operation completed Successfully.

8/ Close down the Command prompt window and Restart your PC for the changes to take effect.

This information was taken from the following webpage:

http://vistasupport.mvps.org/disable_data_execution_prevention.htm

The developers are addressing the issue.