dpnet: Improve Error checking in Get/Set SP (try 4)

[Marvin]

Hi,

While running your changed tests on Windows, I think I found new failures.
Being a bot and all I'm not very good at pattern recognition, so I might be
wrong, but could you please double-check?
Full results can be found at
https://testbot.winehq.org/JobDetails.pl?Key=6257

Your paranoid android.


=== w2000pro (32 bit address) ===
Unable to set the VM system time: the "nc -q0 '10.42.42.139' '4242'" command returned 1