Gnucash doesn't start anymore in Windows

[C. D.]

Sorry for not replying, I got a digest.

With the help of warlord I could create a more meaningful backtrace.
Hope it helps to solve the problem.

---Type <return> to continue, or q <return> to quit---
Backtrace:
In unknown file:
   ?: 11* (if (or # #) (try-load-module name))
   ?: 12  [try-load-module (gnucash report standard-reports)]
   ?: 13  (or (begin (try-module-linked name)) (try-module-autoload name) ...)
   ?: 14* [try-module-autoload (gnucash report standard-reports)]
   ?: 15  (let* (# # # #) (resolve-module dir-hint-module-name #f) (and # #))
    ...
   ?: 16  (letrec ((load-file #)) (dynamic-wind (lambda () #) (lambda () #) ...)
 ...)
   ?: 17* [dynamic-wind #<procedure #f ()> #<procedure #f ()> #<procedure #f ()>
]
   ?: 18* [#<procedure #f ()>]
   ?: 19* (let ((file #)) (cond (# => #) (# => #)))
   ?: 20  [#<procedure #f #> "G:\\Programme\\gnucash-svn\\share\\gnucash\\guile-
modu$
   ?: 21  [load-file #<primitive-procedure primitive-load> ...]
   ?: 22* [save-module-excursion #<procedure #f ()>]
   ?: 23  (let (# #) (dynamic-wind # thunk #))
   ?: 24  [dynamic-wind #<procedure #f ()> #<procedure #f ()> #<procedure #f ()>
]
   ?: 25* [#<procedure #f ()>]
   ?: 26* [primitive-load "G:\\Programme\\gnucash-svn\\share\\gnucash\\guile-mod
ules$
In G:\Programme\gnucash-svn\share\gnucash\guile-modules/gnucash/report/standard-
reports.scm:
 152: 27* [gnc:debug "dir-files=" ...
 152: 28* [directory-files #f]
  94: 29  (let ((dir-stream (opendir dir))) (let loop ((new #) (acc #)) ...))
  94: 30* [opendir #f]

G:\Programme\gnucash-svn\share\gnucash\guile-modules/gnucash/report/standard-rep
orts.scm:94:23: In procedure opendir in expression (opendir dir):
G:\Programme\gnucash-svn\share\gnucash\guile-modules/gnucash/report/standard-rep
orts.scm:94:23: Wrong type argument in position 1 (expecting STRINGP): #f

Program exited with code 02.