ok .. now that we have finally figured out what the problem is, we can get down to resolving it ..
1) If you load the lisp via APPLOAD or the VLIDE it works. This indicates the program is working correctly
2) If you run "off" first, it works. This indicates that "off" changes something that allows "rem" to work correctly
3) If you simply run "rem" it fails ... BINGO ... this is your problem
You have one of a few distinct problems ...
either
a) "rem" is not being loaded at startup
b) you have more than one version of "rem" on the system and the wrong one is being loaded.
c) you have another lisp program already using "C:REM"
d) you have another lisp loading after "rem" loads that changes the function
e) you have an add-on that uses "rem" as its function name
To determine which affects you, there are several things you can do ...
I) Look in APPLOAD and find the lisp file that is loaded that contains "rem" ... i.e. look for your program's file name and verify that the path is pointing to the correct file.
II) At the command line type (type c:rem) ... if it says SUBR then you are at least loading the lisp, if it says nil, then c:rem isn't being loaded.
III) I see from your forum signature that you use Civil3D .. if you also utilize "Raster Entity Manipulation" then you should change the name of "rem" to something else.
IV) Without loading the program via VLIDE or APPLOAD, type the following at the command line: (C:REM) .. if it works properly, you have another program using rem as its name.
Do these and report back ...