I have encountered many ODE problems that produce an
error when displayed. They all give the same error when one
clicks "Try It", an example of which is
Can't use string ("") as a subroutine ref while "strict refs" in use at line 801 of [PG]/macros/PGdiffeqmacros.pl
Died within main::level_curve_check called at line 41 of [TMPL]/rochesterLibrary/setDiffEQ7Exact/ur_de_7_1.pg
I've looked at PGdiffeqmacros.pl but no being a perl programmer
am not able to decide if there is truly an issue.
Any help/pointers would be appreciated.