hi, i was able to replicate the same problem on safari on my win7 machine i get this error:
http://localhost:50000 Assertion failure: A plugin is missing. Check the plugin IDs match in edittime and runtime scripts. Note this can also occur when there is an error in a plugin script that prevents the browser from loading the script - check the error console.
I'm running the last Construct version r95. Did you fix it?