Hi Alison,
The PDF Indexer plugin of Edocman has option to use "Popen" or not. In case you can't enable PHP Popen, you can disable this configure option. And the plugin will use different pdftotext library, but in some cases, this pdftotext library can't index pdf files.
Documents Indexer has the same function with Edocman PDF Indexer, its outstanding feature is the ability to automatically index all documents in a folder.
Thanks
Dam