Debian testing - crashing

[Liz]

I upgraded "a few" packages on my Debian testing/unstable machine and
since then opening a gnucash file with a register window open crashes
the X-server. Opening at the accounts list runs fine, but opening a
register window again crashes the X-server.
There are hints in the trace file

* 09:24:28  WARN <gnc.backend.dbi> [gnc_module_init_backend_dbi()] No
  DBD drivers found
* 09:24:34  WARN
  <gnc.app-utils> /home/liz/.gnucash/config-1.8.auto:13:15: While
  evaluating arguments to gnc:lookup-option in expression
  (gnc:lookup-option gnc:*options-entries*
  "__new_user" ...): /home/liz/.gnucash/config-1.8.auto:13:15: Unbound
  variable: gnc:*options-entries*
  In /home/liz/.gnucash/config-1.8.auto: 13: 0* (let* ((option #))
  ((lambda # #) option)) 13: 1* [gnc:lookup-option ...
* 09:27:51  CRIT <gnc.backend.xml> commodity_ref_to_dom_tree: assertion
  `c' failed


so i renamed the old 1.8 config files 
and tried again

* 09:37:10  WARN <gnc.backend.dbi> [gnc_module_init_backend_dbi()] No
  DBD drivers found

I'm using xml backend, gnucash 2.4.7  built from rb5bdf19+ on
2011-08-01.
this started with a later gnucash so i had downgraded to 2.4.7


Has anyone already solved this problem??