Launching Toad for Data Analyst gave "There is not enough space on the disk." (4290418)

When I double click on the Toad for Data Analyst icon to launch it, I get the following error:

   System.IO.IOException
   There is not enough space on the disk.

Possible cause could be a lack of rights to the following directory:

   C:\Documents and Settings\<your_user>Application Data\

When Toad for Data Analyst first launch, it needs to create files into the following directory:

   C:\Documents and Settings\<your_user>\Application Data\Quest Software\Toad for Data Analysts <version>

Check

   C:\Documents and Settings\<your_user>\Application Data\

and you'll see that the Quest Software folder was not created and hence the Toad for Data Analysts folder will not be created either.  You might still be able to right-click and create any folder but the issue is not your user but the toad.exe being able to read/write there.  Please ensure that the toad.exe with your Windows user can read/write to the path stated.