APR::Table sporadic error

Hi All,

We have a modperl application that is an online homework system for math
courses called webwork.  My installation and a few others have seen a
sporadic error from APR::Table that nobody quite knows how to diagnose.
 Here are two typical examples:

Example 1:
Can't locate object method "get" via package "APR::Table" at
[WW]/lib/Apache/WeBWorK.pm line 74
Died within AnswerEvaluator::evaluate called at line 1 of (eval 1321)
System: Ubuntu 8.04, Apache 2.2

Example 2:
Failed to initialize course environment: Could not evaluate global
environment file /opt/webwork/webwork2/conf/global.conf: Can't locate object
method "get" via package "APR::Table" at
/opt/webwork/webwork2/lib/Apache/WeBWorK.pm line 74.
RHEL 5 with RedHat's build of Apache 2.2.3. 1 GB RAM, perl-status shows
ARP::Table is loaded.
APR::Table 0.009000 Fri Sep 19 04:30:28 2008
/usr/lib64/perl5/vendor_perl/5.8.8/x86_64-linux-thread-multi/APR/Table.pm

I'm hoping you might be able to provide some suggestions of where to start
looking for the source of this problem.

The modperl handler is here:

http://webwork.maa.org/viewvc/system/trunk/webwork2/lib/Apache/WeBWorK.pm?view=markup

The error was not seen (and has not been seen) running mod_perl 1.  Here is
a report from one user:

We've seen the APR::Table error sporadically, and have found it to be
> chronic and page load dependent. We've found in every case that if we reload
> the page the error will go away. Our hypothesis is that it's probably a
> thread initialization problem, and that it shows up when the apache process
> hands the WeBWorK job off to a new thread that doesn't have all of the
> required Perl loaded before the it tries to execute the WeBWorK request.
> That said, we don't know much about thread management in apache, so we don't
> know if that's even credible.


Any hints/tips/ideas would be very much appreciated.

Thanks,
Jason