could you post your code so we can have a look.
web_sync will wait for your browser to stop loading. If your browser is still working after the amount of time you put in web_sync then you will get the failure.
Web_sync is a TSL function that tells the test to wait for a specific amount of time and reports a fail is this the expected action has not occured within the defined time limit. search for the web_sync function in your code. if it is not found in that specific script look for any 'load', 'reload' or 'call' calls and check the files mentioned by these.
If the the app is timing out this may also be a valid bug as the web_sync time should be set to what is an acceptable response & load ime defined in your specs. if it is set to low find out the specified response time and adjust it. otherwise raise it as a bug and reccomend some performance testing.
Every time they make idiot proof software. The Universe goes and makes a better idiot