This is Production Printing 101. That error message sounds like you are just using tray calls on the Fiery (which is bad practice); and the paper type "color specific" and the weight "81-105 gsm" are the Fiery defaults, which you haven't changed in the job properties (which is good practice).
Paper is defined by three parameters: size, weight, and type. You must set up your paper tray(s) according to these parameters at the engine console. Size, the machine will get from the position of the guides (except for custom-size papers), so don't worry about that; however, you must punch in weight and type. Look on the ream label for the weight, expressed in gsm, and punch that in. Is the paper coated or uncoated? Is it made for digital? That too will be on the ream label. Examples: Hammermill 28# Color Copy is 105 gsm, paper type Color Specific. Ordinary office paper is 75 gsm, paper type Plain. Coated stocks, like Futura, Mohawk, Endurance, come in 80# text (118 gsm), 100# text (148 gsm), 80# cover (216 gsm), 100# cover (271 gsm), among other weights. You must select the weight range into which these numbers fall, for the paper you are using. The paper type for coated stocks is Coated-GL (for glossy) or Coated-ML (for matte, dull, or silk), among others. All of these settings are made at the engine console.
When setting up the job in Fiery job properties, under the Media tab, you must make the same selections, so that the paper you request for the job matches up with the paper you have defined on the machine. Do not let them default, and do not bother selecting a tray number (always leave the tray setting on "Auto Select").
Assuming the technician has installed the machine properly, when the paper parameters in your job settings match with those of the paper settings for the tray on the machine, the job will run without erroring out the way you saw it do.
