Good catch! Here is updated logic...

EXEC @x = sp_OACreate 'Scripting.FileSystemObject', @iFSO OUT

IF @x <> 0

RETURN -1

EXEC @x = sp_OAMethod @iFSO, 'GetDrive', @iDrive OUT, @cDrive

IF @x <> 0

GOTO Error

EXEC @x =...

----The following will return each local drive and a free space in MBEXEC master.dbo.xp_fixeddrives

----The following function with obtain a supplied drive's capacity

ALTER FUNCTION [dbo].[fnDBDriveStats_GetDriveSize]

(@cDrive char(1)) ...