>lStartPath = getdir()
>lRootPathName = iif(len(lStartPath) >= 3, left(lStartPath, 3), "") + chr(0)

This is not an error, but the chr(0) is useless here.

>lSectorsPerCluster = 1
>lBytesPerSector = 2
>lNumberOfFreeClusters = 3
>lTotalNumberOfClusters = 4
>
>if empty(lStartPath)
>
> return && cancelled
>
>else
>
> if !GetDiskFreeSpace(lRootPathName, ;
> lSectorsPerCluster, ;
> lBytesPerSector, ;
> lNumberOfFreeClusters, ;
> lTotalNumberOfClusters)

The problem is that you must pass all params by reference, ie put a @ in front of all params. Is not enough to declare them as passed by reference. You need to actually pass them by reference.

Vlad