System and SystemQQ: what am I doing wrong?

Hi,

I want to do something that is quite simple (I reckon).  I must go up one folder level, chdir to another folder and then delete one existing file in this latter folder.  What I'm doing is the following:

         Logical :: I

         I = SystemQQ('cd ..\Data\')
         I = SystemQQ('del CPG.dat')

However, it seems that not even the first command works, I mean, I cannot go up one level and then into the Data folder.  The command System (by the way, in what it differs from SystemQQ?) doesn't work either.  Same result if I split the first command:

         I = SystemQQ('cd ..')
         I = SystemQQ('cd Dados')
         I = SystemQQ('del CPG.dat')

What am I doing wrong?  My system's specs are appended below.

Thanks a lot for any help.

Fausto

Windows 7

Microsoft Visual Studio 2005
Version 8.0.50727.867  (vsvista.050727-8600)
Microsoft .NET Framework
Version 2.0.50727 SP2