Problem login with Java Desktop System, Release 3 on Solaris 10 x86

According to my project in the laboratory I seem to have to switch to use Solaris, because I have to work on portlets in Sun One Portal Server. My guider decided that I have to work with Sun One Portal Server in Solaris.
So I installed Solaris 10 x86, which comes with JDS 3. It looks so great, +1 to Solaris guys. But I soon encountered a problem with login into JDS 3: when I logined, I usually received such error messages:
"There was a problem registering the panel with the bonono-activation server.
The error code is: 3.
The panel will now exit"
and
"Nautilus can't be used now, due to unexcepted error from Bonono when attempting to register the file manager view server."
And then I can't use my JDS 3, the screen was freezing!
I've asked people in newsgroup comp.unix.solaris, but I solved that problem before receiving the solutions.
That is I have to delete all file in directory /var/tmp, then everything becomes normal again! Yeah!
But I also received a good solution from comp.unix.solaris which helps me get out of this problem forever :)
Just change the evironment variable TMPDIR to /tmp :
Add this line to the file ~/.dtprofile:
export TMPDIR=/tmp