It sounds like your frame titles have been changed/dont’ exist. Did you have to convert the FLA to open it in your Flash? Are you sure you are editing the original file and that it was programmed in the same Flash Version? gotoAndStop is not a complicated function, so it just must not be able to find ‘flashmo_photo1′ or ‘page’
The file I used is the one that is set to automatically open in Adobe Flash Editor (don’t know file extension at this moment… on my work computer). All I did was edit the title in the header and save the file and export a new image file.