A problem that you are seeing has nothing to do with the Firefox profile.
Actually, it is related to the JVM class loader that complains that it can't you’re your
This actually means that you don't have a Guava (which is the dependency for Selenium) on the class path. So you need to clean and rebuild your project and check the classpath also check your various versions of all the libraries that might be there. If you are trying to use some kind of a dependency management system like (Maven, Ivy etc.) then you need to check if it is configured correctly.
A standalone package can be downloaded from the below link:
If you are not using it currently, the easiest solution is to switch to a standalone version.