--- Here are some possible error messages you might encounter. impossible error in derivs! should not happen No parameter file! Could not open parameter file looking for foo.p after invoking react foo insufficient memory Could not open mechanism file looking for foo.m after invoking react foo too many reactants + species no reactants or products insufficient memory insufficient memory bailhelp Could not open results file could not create foo.r after invoking react foo reduce tolerances integrater is not achieving desired tolerance, try a lower (larger numerically) tolerance, 0.0001 is often good. possible singularity there may be something wrong with your reaction mechanism make sure it is correct not converging the integrater is failing to converge, check the mechanism can it be simplified? component vanished one of the species in the mechanism is too darn close to zero, increase abs. tolerance may be required code problem should not happen Cant open output file for species list could not create foo.s after invoking react foo In addition the core intergrater might complain with some problems. If this happens, or the integration is too slow reduce the tolerance requirements (make them larger). --- When reporting problems please email a copy of the foo.m and foo.p files, state the machine used to run react (sun, msdos, etc), and if possible the output (or relevant parts) from react.