[horde] Compose message in DIMP doesn't work

[IT]

Hello

I installed DIMP today on a platform with updated and working IMP (& 
horde framework)
    * Dimp: H3 (1.1-RC2)
    * Horde: 3.2.2
    * Imp: H3 (4.3-RC2) (run Imp tests)
    * Ingo: H3 (1.1) (run Ingo tests)
    * Mimp: H3 (1.0.1) (run Mimp tests)
    * Turba: H3 (2.1.4) (run Turba tests)

Nearly everything is working nice.

But in DIMP the menu-point "Compose" doesn't work. If I click, 
nothing is happen. If I mark a message and choose answer a 
composewindow is getting open. Any Ideas?

Another question by the way: What's the easiest way to get the people 
to DIMP after login?

Thanks a lot an sorry my bad english...

Greetings Stephan