[imp] DIMP - login.php not found

[Deon de Villiers - Hetzner (Pty) Ltd]

Hi

I have installed DIMP Version 1.0-cvs (as as add on the the Horde 
Webmail edition version 1.0.3 - ie. Horde framework version) and I 
upgraded IMP to 4.2-Alpha.

When browing to DIMP, I receive the following error:

Fatal error: Call to undefined function: 
array_merge_recursive_overwrite() in 
/usr/www/users/hdiary/hordenew/dimp/lib/base.php on line 95

Anyone able to point me in the right direction to resovle this?

Thanks
Deon.