I am having problems when trying to print directly from an IQ series instrument to a printer.
The IQ series instruments can "talk" in two printer languages: Hewlett-Packard and Epson. Both "languages" can be used with printers of many different manufacturers, not only HP and Epson. Check the manual of your printer for the correct language and set it in SET-Mode 14 of your IQ. HP=PCL 4 or PCL 5 Epson = ESC/P2
The sequencer of connecting the printer and vario can make a difference: First switch on printer and IQ instrument. Then connect cable to printer and last connect to IQ.
Check your hardware, is the printer cable OK? Check with the cable of your friend. Also check with another printer.
Are you sure the flight you want to print out really has barogram data stored? Try printing the flight log instead.
Please check all cables for tight fit in the ports and also if they are plugged into the correct ports.