Problem using the library FIXED

Problem using the library FIXED

by Arnold Pizer -
Number of replies: 1
This is a synopsis of solutions given in the long thread "Problem using the library" . That thread is so long that people may miss the solutions.

The "Problem" is that in WeBWorK 2.7 the Library Browser will not add problems to a homework set.

There are three causes to this problem that we know of: (1) a mis-configured URL, (2) courses need to be upgraded and (3) trouble with Perl modules.

(1) A mis-configured URL is easy to check and fix. The "Add" button will not work in the Library Browser if in the site.conf file (in /opt/webwork/webwork2/conf/), $server_root_url is not configured correctly.  Most other parts of WeBWorK will work, but the  Library Browser will not.

(2) If you are using a course created with another version of WeBWorK, go to the admin course to upgrade it.

(3) Problems with Perl modules can be more subtle.  First run " apache2" from webwork2/bin.  Obviously, if there are any problems, they should be corrected.  But the trouble may be deeper.  "Modules from CPAN were at their latest CPAN version. The problem was that some of them needed to be of versions in Ubuntu 12.04.2 instead. I didn't find out which modules in particular." To fix this "We had much more in /usr/local/lib/perl/ and /usr/local/share/perl/, than in WeBWorK VM. Though WeBWorK 2.7 itself was installed fresh, quite a few Perl modules remained from previous installs, when they still had to be installed from CPAN. Of course /usr/local/ was overriding whatever came from Ubuntu repos. Removed /usr/local/.../perl/, reinstalled only a few modules, that are still needed from CPAN and all is fine now, i.e. "Add" in Library Browser works.

If you have tried the above and still have problems , here are some hints on trouble shooting.

It might help to edit webwork2/lib/ to set UNIT_TESTS_ON to 1 (near line 90), restart apache, cause the error, and report the added diagnostics from the apache error log file.  (Then set it back.).  For example the following in the error log signaled a problem with perl modules under /usr/local/. 
[Mon Aug 05 10:22:22 2013] [error] [client] Illegal field name 'APR::Table=HASH(0x7fb40e19b708)' at /usr/local/share/perl/5.14.2/SOAP/Transport/ line 818.\n

If you have a virtual machine environment available (VMware, VirtualBox, etc) you might grab the virtual machine image (  and then try to figure out what is different between your set up and the virtual machine set up.


In reply to Arnold Pizer

Re: Problem using the library FIXED

by Dave Rosoff -
I experienced a similar problem on our server, running 2.7 and using LDAP authentication.

While running through the solutions listed here, I noticed some errors that seemed to indicate a problem verifying our SSL certificate. After some checking with our helpful IT staff, I added three lines to /etc/apache2/ssl.conf:

SSLCertificateFile /path/to/
SSLCertificateKeyFile /path/to/
SSLCertificateChainFile /path/to/crtfile.crt

This seemed to resolve the problem.

Anyone using SSL and having trouble with the Library Browser might find this useful.