Gimp: trouble printing in color?

It doesnt matter what I print in color it always comes out with a brown layer on top of all other colors but black is fine.

I made logo for a small business and made a business card, the black vector image came out perfect and clear since it was high res but the light grey color next to it came out a light olive.

i.e. the card is two back ground colors, one side white with the logo and the other light grey with the details, all on one side no back to back.

On another instances I made a poster for a club, high res yet it still came out with a brown layer, all the colors looked weird.

Do I have to save the Jpeg as Png or do I have to fiddle with the color management etc.

General setting at 72ppi and set as RGB.

Its perfect on screen but printing screws it up!

WTF??????????????????

HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!