You have a syntax error. The best way to debug this is to break up the command string you are sending to the instrument and look at what part of the string triggers the error. Make your self a little VI that has 1 string control as input and then does a VI write to the 6517, then a VI read response and error. Enter the strings one at a time until you hit the error. Look up that specific command in the manual (500 pages reduced to perhaps 2pages!) and see if you have the string correct. Does it require something you omitted? Wrong separators? Wrong colon/semi-colon? Etc..
If you attached the real VI I might have a look to help, but nothing I can do with images of the code.
OK I'll try that and get back to you (device not with me now). Here is the VI.
Today I happened to be in a lab with a 6517a, so I borrowed it for the afternoon.
This is code that implements the solution gregoryj pointed out above. It works!
Rather than modify the driver VIs I implemented a complimentary set for using with temperature measurements. So leave the original in place and use these along side..safer this way!
There are two examples: