PDFText Error

i'm using omeka version 2.03 and i've installed PDFText plugin version 2.
i got error message when i was trying to upload a pdf file.
this is the error message:

Zend_Db_Statement_Mysqli_Exception
Mysqli statement execute error : Column 'text' cannot be null

#0 /home/u939302100/public_html/application/libraries/Zend/Db/Statement.php(303): Zend_Db_Statement_Mysqli->_execute(Array)
#1 /home/u939302100/public_html/application/libraries/Zend/Db/Adapter/Abstract.php(479): Zend_Db_Statement->execute(Array)
#2 /home/u939302100/public_html/application/libraries/Omeka/Db.php(79): Zend_Db_Adapter_Abstract->query('INSERT INTO `om...', Array)
#3 /home/u939302100/public_html/application/libraries/Omeka/Db.php(252): Omeka_Db->__call(Array, Array)
#4 /home/u939302100/public_html/application/libraries/Omeka/Db.php(252): Omeka_Db->query('query', Array)
#5 /home/u939302100/public_html/application/libraries/Omeka/Record/AbstractRecord.php(543): Omeka_Db->insert('INSERT INTO `om...', Array)
#6 /home/u939302100/public_html/application/models/Mixin/ElementText.php(624): Omeka_Record_AbstractRecord->save('ElementText', Array)
#7 /home/u939302100/public_html/application/models/Mixin/ElementText.php(85): Mixin_ElementText->saveElementTexts()
#8 /home/u939302100/public_html/application/libraries/Omeka/Record/AbstractRecord.php(251): Mixin_ElementText->afterSave()
#9 /home/u939302100/public_html/application/libraries/Omeka/Record/AbstractRecord.php(280): Omeka_Record_AbstractRecord->delegateToMixins(Array)
#10 /home/u939302100/public_html/application/libraries/Omeka/Record/AbstractRecord.php(550): Omeka_Record_AbstractRecord->runCallbacks(Array, Array)
#11 /home/u939302100/public_html/application/models/Item.php(322): Omeka_Record_AbstractRecord->save('afterSave', Array, true)
#12 /home/u939302100/public_html/application/models/Builder/Item.php(204): Item->saveFiles('afterSave', Array)
#13 /home/u939302100/public_html/application/libraries/globals.php(554): Builder_Item->addFiles()
#14 /home/u939302100/public_html/application/models/Item.php(307): insert_files_for_item()
#15 /home/u939302100/public_html/application/models/Item.php(217): Item->_uploadFiles()
#16 /home/u939302100/public_html/application/libraries/Omeka/Record/AbstractRecord.php(277): Item->beforeSave('Upload', 'file', Array)
#17 /home/u939302100/public_html/application/libraries/Omeka/Record/AbstractRecord.php(531): Omeka_Record_AbstractRecord->runCallbacks(Object(Item), 'Upload', 'file', Array)
#18 /home/u939302100/public_html/application/libraries/Omeka/Controller/AbstractActionController.php(175): Omeka_Record_AbstractRecord->save()
#19 /home/u939302100/public_html/application/controllers/ItemsController.php(88): Omeka_Controller_AbstractActionController->editAction(Array)
#20 /home/u939302100/public_html/application/libraries/Zend/Controller/Action.php(516): ItemsController->editAction(Array, Array)
#21 /home/u939302100/public_html/application/libraries/Zend/Controller/Dispatcher/Standard.php(308): Zend_Controller_Action->dispatch('beforeSave', Array)
#22 /home/u939302100/public_html/application/libraries/Zend/Controller/Front.php(954): Zend_Controller_Dispatcher_Standard->dispatch(false)
#23 /home/u939302100/public_html/application/libraries/Zend/Application/Bootstrap/Bootstrap.php(97): Zend_Controller_Front->dispatch()
#24 /home/u939302100/public_html/application/libraries/Zend/Application.php(366): Zend_Application_Bootstrap_Bootstrap->run()
#25 /home/u939302100/public_html/application/libraries/Omeka/Application.php(79): Zend_Application->run('editAction')
#26 /home/u939302100/public_html/admin/index.php(28): Omeka_Application->run(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http))
#27 {main}

what should i do? can anybody help me?

It looks like the plugin isn't able to produce any text from the PDF. Not sure where the problem might be.

Is this happening for all PDFs that you've tried, or just some of them?

it's happening for all PDFs

It could be, then, that something on the server is configured to not allow the pdf extraction. The plugin uses the shell_exec() function, which is sometimes turned off on servers. It is also possible that the pdftotext application on the server is not there. Those are things to check with the server administrator