The following error messages have been observed in building the GFPM. They should not occur in normal use of the model, but only if extensive changes are made.
BAD ROW: This message may appear when the solver encounters a bad row in the MPS file. This is the file LINDO, called "matin.dat"; see the LINDO manual for a description of MPS files). The problem may occur as a result of incorrectly formatted or missing information in the file input file (WORLD.xls, AFRICA.xls, etc.).
INFEASIBILITY: This problem arises as a result of constraints binding too tightly, so that no solution satisfies all the constraints. Loosen any recently imposed constraints until a solution is found.
RUN-TIME ERROR: Pascal, the programming language of the GFPM, is unable to read numbers larger than 11 digits. It may be necessary to reduce the size of some parameters if this problem occurs. For example, an unreasonably high rate of GDP growth will lead to huge demand in large countries in future years, which may cause a run-time error.
UNBOUNDED SOLUTION: The LINDO solver maximizes the areas between the demand and supply curves less manufacturing costs. This occurs when the demand and supply curves are incorrectly specified, so that the area between them can be infinite.