--- trunk/reactos/base/setup/usetup/drivesup.c
(original)
 +++ trunk/reactos/base/setup/usetup/drivesup.c Tue Oct  2 16:16:45 2007
 @@ -35,7 +35,8 @@ 
...
  +      if (Ptr)
 +          RtlCreateUnicodeString(SourceRootDir, Ptr);
 +      else
 +          RtlCreateUnicodeString(SourceRootDir, L"");
 +
       if (Ptr != NULL)
 -      *Ptr = 0;
 -
 +          *Ptr = 0; 
You can put *Ptr = 0 in the if-else
Pablo