Hello,
On Friday I was having a similar problem with the DEC5 and HSEROUT but I am not sure if is this "bug" or if my ADC was dead. Tomorrow I will check at work.

Now I tested in a 18F4680 at home:

Walue = 100 'also defined as word
HSEROUT [DEC5 Walue,10,13]

and the terminal shows "100" as expected, using PBPro, compling with MPLAB, so it seems to work fine.

By the way, aren't you mixing up the LCD commands with the HSEROUT?
$FE etc.. is used in the LCDOUT command, that has a different sintax than HSEROUT.

JM