HTML::Mason and MLDBM

[kilinrax]

While attempting to convert some code to run on a Debian/Stable box†, I have encountered an error that has me truly stumped.
I have a script that generates static HTML pages using data from a dbm, and templates used by the dynamic ortions of the site - thus it needs to use HTML::Mason and MLDBM at the same time. However, the line that ties the dbm:

tie %Data, 'MLDBM', 'linkdata.dbm', O_RDONLY, 0640 or die "Tie Failed 
+on 'linkdata.dbm': $!\n";

generates the following error:

MLDBM error: Second level tie failed, "No such file or directory" at .
+/dbmreader_mason.pl line 34
Tie Failed on 'linkdata.dbm': No such file or directory

The file is clearly there; I can see it, and wrapping the offending line in 'if (-e $filename) { ... }' still causes it to be executed. There is no NFS or symlink weirdness going on, the file has the right permissions, and it happens irrespective of whether I use an absolute path or not.
I know this is a Mason issue, as removing all references to HTML::Mason causes the script to run without errors (though also without doing anything useful).
I have a vague recollection of something similar happening when the options given to MLDBM in the script are different from those in Mason's configuration ('/etc/apache/mason_handler.pl', iirc) - but in this case, both are using DB_File and Storable.

Anyone experienced anything similar or have any advice?

†: This means I'm using Perl 5.053, Mason 0.72-1 and MLDBM 2.00-6. Unforunately I don't have root on this machine, so installing newer versions of packages is not an option.