www/horde does not run on 10-STABLE - Fatal Error: Could not pack data

[Per olof Ljungmark]

Sorry for the cross-post but this is a bit out of the ordinary for me.

In short, no matter how I try varoius changes, I am unable to run
www/horde-base under latest 10-STABLE. The error is:

HORDE: Could not pack data. [pid 80949 on line 154 of
"/usr/local/share/pear/Horde/Pack.php"]

>From what I gather, Pack.php deals with compressing data before cache,
maybe also before sending to browser. Problem occurs both through Apache
and with php cli.

Facts:
The same config ran on 10-STABLE mid-August
Stopped working after updating to latest 10-STABLE end last week (27th.)
Same config runs fine on 9-STABLE. Today I did a fresh 9-STABLE, got
Horde up and running fine. Updated the system to 10-STABLE. rebuilt all
ports and the error is back.

Please, if anyone has ANY idea what is going on? If I was fluent in PHP
I assume I could figure out myself...

Thank you!

//per