I am seeing the same issue here on multiple Blackberrys when accessing a customized (company branded) recruiting site. The company providing the site says that no other customers have reported any issues, but we are getting it on multiple devices with versions 4.2 up (I don't have anything older to test).
"Handler could not be attached" is the error and you can select "OK" multiple times to bypass the error. Everything appears to function.
Any assistance in finding a useful error (maybe logged somewhere...) would be appreciated. It is management that uses the app, so hitting OK a few extra times is simply not acceptable