The application ran your source text through the Inform 7 compiler, as usual, but the compiler unexpectedly failed. This should not happen even if your source text is gibberish, so you may have uncovered a bug in the program.

This seems to be an unusual case, because the failure code is not one which has ever been observed in Inform's testing process, so it is difficult to give advice. Still, further details may be visible on the console output in the Progress tab.

The best option now is probably to reword whatever was last changed and to try again. Subsequent attempts will not be affected by the failure of this one, so there is nothing to be gained by restarting the application or the computer. A failed run should never damage the source text, so your work cannot be lost.

If you think it likely that the Inform 7 compiler is at fault, please check that you have the currently distributed build of the system: if you have, please consider taking the time to fill out a bug report form and email it to the author. If you think the fault may be due to a problem in an extension you're using, then please contact the extension's author directly.