VirtualBox: The value of the Base Memory field on the System page is not complete

[kron]

Greetings,

I'm running virtualbox-ose-4.2.14 on FreeBSD 9.1-STABLE r252094M
amd64. The GUI of VirtualBox cannot create/update virtual box
definitions (the *.vbox) files. The scrollbar and the form field
for "Base Memory" are broken and the following error message
is displayed:

"The value of the Base Memory field on the System page is not
complete."

I guess it comes from the base memory upper bound preset to zero
but I have no clue what's the source for the zero value.

The problem is just in the GUI:
- I can create or update VMs using the CLI
- the VMs created in older VirtualBox versions run fine

I anyone facing the same problem?

BR,
Oli