What do you mean by "debug mode"? Are you talking about highlighted execution? Where you can watch how the program progresses in the block diagram? I've seem some instances where highlighted execution slows systems down enough that errors don't occur. One of things that you could do to try to catch where/why your error is occurring is to use conditional probes on the error wires in between the different subVIs of your application.
To create a conditional probe, right click on any error wire, choose Custom Probe >> Conditional Error Probe. This will bring up a dialog with information about the probe you are setting. Clicking the Condition tab will allow you to choose the conditions that will cause your program to pause. Run your program without highlighted execution, and if you've probed correctly, your application should pause the moment any of the conditions you set in your probe are met. You can then investigate further the cause of your troubles.
I'd recommend this, because I wasn't able to find any documentation for an error code N410. Could you give more information about this error code? Does the error screen that pops up tell you which VI the error occurred at? Or which particular instrument you are working with? There's a chance that is a custom error code for a Keithley instrument, in which case we'll have to do some checking with them.
As far as measuring the voltage without turning on the current goes, that once again is something that we'd have to check with Keithley on. If it is possible, then you should be able to configure the instrument to do so. But check with Keithley to be sure.
Logan S.
