99% of technical problems are due to incorrect browser "cache" settings.
The browser cache stores pages downloaded to your computer from the Internet. As you work, Etudes is continually updating and storing pages in a database that is on a remote server, not locally on your computer. The browser must be set to always go out to the server and get new pages from the server and to not use old pages stored on your computer or errors will occur.
Click on the Firefox Menu > Select Preferences
Click on the Advanced icon > Click on the Network tab
Enter 1 MB of disc space for the cache, then click on Clear Now button
Close the Preferences window > Quit and Restart Firefox
Open a browser window, delete the address in the URL bar and type about:config. Press the Return key to see Firefox settings. NOTICE: Do not include the http prefix here!
Scroll down to browser.cache.check_doc_frequency. It should be set to 1. If it's not, double click on the text and in the resulting dialogue box, enter 1 and click OK.
Quit and restart Firefox to enact the change.