In case of compilation error Resin shows a simple page with the only message:
Server Error
The server is temporarily unavailable due to an internal error. Please notify the system administrator of this problem.
And all significant information I should seek in the log file.
Is it possible to redirect somehow all error diagnostics to the browser window?
Try setting <development-mode-error-page/> tag to true. In later versions of Resin the value is externalized into resin.properties:dev_mode
http://caucho.com/resin-4.0/reference.xtp#developmentmodeerrorpage