Sorry about that, I was sleepy and I did a mistake, actually there is no problem with the bindPotentiallyConflictingTypes, the problem is with the DwrGuiceServletModule class, line 112. This line makes dwr incompatible with google-guice 2.0. It generates the following error:
1) A binding to javax.servlet.ServletContext was already configured at org.directwebremoting.guice.DwrGuiceServletModule.configure(DwrGuiceServletModule.java:112).
I don't know exactly the structure of DWR, but I would suggest to add a annotatedWith version and to put this line also inside the IF of line 76. I did this change and now it's everything work perfect. I've also attached a patch, please take a look on it.