this tutorial on exception handling might be helpful
http://wiki.processing.org/w/Exceptions

I tried this script:

Ok after reading the reference for open() and poking around in the source code i'd say that you won't get a error if the file won't open. Simply put open(path) runs the following command on a windows "cmd c path" which will always execute, even if you give it a invalid path, because cmd itself will always run successfully and the "path not found" error will the internal to the cmd and there is therefor never thrown an exception.

So from what i can tell there is no easy way of knowing if open() ran successfully. I would however recommend you to use the File class that is built into java and use it's exists() method to check if the file exists before using the open() method..

problem solved,