It has been noticed that, when running the "RCF1.ogb" example immediately after installation, the program sometimes halts with the error message "Dynamic Run Error (1): TPV went QNAN!" This is due to a very slight oversight on the programmer's part, but it is readily remedied!
Close the program and restart it; then, before running the model, select "Preferences" from the "Options" menu, and go to the "Run-Time Limits" property page. Therein, change the "I tolerance" value from its default of 1e-21 to 1e-20; you should now be able to run the model without problems. (Also, this change will be saved across sessions.)
Apologies for the inconvenience.
Adrian