Your step pulse polarity is correct, although the pulses are a bit long - 5 us should be sufficient. Do you have the XML file for this machine, or are you setting it up from scratch? If you contact Kurt at Taig he can send you the XML file that sets up Mach3 with all the recommended initial settings, and he'll help you troubleshoot it from there.
Do check all the obvious things first, like lubrication (you need to lube all the screws and slides with oil (they recommend red ATF; I prefer #2 medium way oil) A little stiction will cause those errors. Another thing you might try is re-downloading and reinstalling Mach3 - sometimes a corrupted program can cause those errors too.
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