You need to check your configuration. If your using a 1747 pic you need to make sure that your configured and running that driver for the pic. You may need to stop your driver and restart. You might have to do an "Auto Config" after you make sure you have the right driver configured.
rs232 df-1 the firt one on the list
diskette 1747-uic serA
USB to DH485 interface converter
That's the right driver. Here's the manual if you don't have it.
http://literature.rockwellautomation.com/idc/groups/literature/documents/in/1747-in063_-en-p.pdf
And BTW do not click on autoconfigure ( says the manual)