problems installing PTB (3.0.9) under R2009a - search path lost

1
Dear all,

I installed PTB-3 (3.0.9 - Flavor: beta) using matlab 7.8.0 (R2009a) on
my macbook pro (Mac OS X 10.6.7). The installation seemed to work fine:

>> PsychtoolboxVersion

ans =

3.0.9 - Flavor: beta - Corresponds to SVN Revision 2150
For more info visit:
http://svn.berlios.de/wsvn/osxptb/?rev=2150&sc=0


...however, when I switch to another folder (e.g. PsychDemos), PTB seems
to be gone:

>> PsychtoolboxVersion
??? Undefined function or variable 'PsychtoolboxVersion'.

When I restart matlab, I receive a lot of error messages:

Warning: Name is nonexistent or not a directory: current/Psychtoolbox.
Warning: Name is nonexistent or not a directory:
current/Psychtoolbox/.FBCLockFolder.
Warning: Name is nonexistent or not a directory:
current/Psychtoolbox/PsychAlpha.
...etc.

Indeed, all the PTB folders in the matlab search path are gone.


The same PTB version under matlab 7.6.0 (R2008a), which is still
installed, works fine:

>> PsychtoolboxVersion

ans =

3.0.8 - Flavor: beta - Corresponds to SVN Revision 1942 but is *locally
modified* !
For more info visit:
http://svn.berlios.de/wsvn/osxptb/?rev=1942&sc=0

(but note the slight differences)

I re-installed PTB-3 and also matlab 7.8.0, but the problem persists.
Weirdly, one time the PTB folders reappeared in the search path, but I
was not able to reproduce this.

I tried to disenable and re-enable the toolbox path cache, without success.
I have no real clue what the problem could be about, so I would be very
thankful for any help!

Best regards,
Moritz