kmail library problem

I've just upgraded to Debian Jessie, and things seem to work, with two exceptions: 1 I couldn't run xinit /opt/trinity/bin/startkde because ksmserver-trinity was not reinstalled by default. I think because of dependency problems, since I had to downgrade a few packages to get it to install. But that is now sorted. 2 Having got Trinity to run, everything (so far) seems to work except kmail, my favourite program! 4:3.5.13.2-0debian7.0.0.+0 has been installed. I get the following: 23:40 ~>kmail kmail: error while loading shared libraries: libkmailprivate.so: cannot open shared object file: No such file or directory But it's there... 23:41 ~>la /opt/trinity/lib/libkmailprivate.so -rw-r--r-- 1 root root 8071664 Jun 14 2013 /opt/trinity/lib/libkmailprivate.so It seems to be the only file with this problem - it has the same permissions as all the rest. Where do I look next? And before you ask, no, I'm not using kmail to write this, but webmail, so sigs and things are a bit different... cheers ant