Error in Index On Save: Cannot open file
This is a known bug with IslandWrite from the IPS 5.0.2 release.
If the error message really bugs you, you can get rid of it by renaming the IslandInTEXT startup script in the $IOFFICE/bin. For example, you could rename it to IslandInTEXT.old. But, you would only want to do this if you did not intend to use IslandInTEXT.