Here is the code for this problem that was working previously.
When i look up the particular address from the (270 Library) the problem reads in pink letters:
This problem produced an error.
1.) Is it because that this is a very old problem?
It was working fine a few days ago.
# This file is just a pointer to the file
#
# "Library/maCalcDB/setDerivatives20Antideriv/ur_dr_20_1.pg"
#
# You may want to change your problem set to use that problem
# directly, especially if you want to make a copy of the problem
# for modification.
DOCUMENT();
includePGproblem("Library/maCalcDB/setDerivatives20Antideriv/ur_dr_20_1.pg");
ENDDOCUMENT();
## These tags keep this problem from being added to the NPL database
##
## DBsubject('ZZZ-Inserted Text')
## DBchapter('ZZZ-Inserted Text')
## DBsection('ZZZ-Inserted Text')