Flash Player can't write or read from the local shared objects in the user's redirected home directory because we disallow traversing junctions (soft links for the non-Microsoft folks) in the broker process. This behavior was disabled to address a vulnerability identified in some of John Forshaw's research into the IE broker earlier in the year.
If you don't want to change your infrastructure, you can enable this behavior by adding the following setting to mms.cfg:
That said, you can probably gather from the name of the flag that we don't really recommend this approach, and disable this attack surface by default. There's some risk that a network attacker could craft content that abuses fundamental issues with how Windows handles Junction Points to write to arbitrary locations.
More on Junction Points can be found here:
If you're going to live with this attack surface, it's probably worth your time to watch James Forshaw's talk on IE sandbox escapes, which prompted these changes:
Thank you for your quick and prompt answer. I was able to, temporarily fix this based on your response.