Uploading images in Omeka 1.5.3

Hello,

I just installed an older version of Omeka (1.5.3, in order to run UIowa's fork of Scripto), and am having some problems uploading images when I add items. While I have succeeded in uploading a couple of small jpegs, more often Omeka says it encounters an error after the upload. The error log reads as follows:

#0 /home2/beloitm1/public_html/omeka15/application/libraries/Omeka/File/Derivative/Image.php(114): Omeka_File_Derivative_Image::createImage('/tmp/35be7c4214...', '200', 'thumbnail')
#1 /home2/beloitm1/public_html/omeka15/application/libraries/Omeka/File/Derivative/Image.php(222): Omeka_File_Derivative_Image::createDerivativeImages('/tmp/35be7c4214...')
#2 /home2/beloitm1/public_html/omeka15/application/models/File.php(248): Omeka_File_Derivative_Image::createAll('/tmp/35be7c4214...', 'image/jpeg')
#3 /home2/beloitm1/public_html/omeka15/application/models/File/ProcessUploadJob.php(24): File->createDerivatives()
#4 /home2/beloitm1/public_html/omeka15/application/libraries/Omeka/Job/Dispatcher/Adapter/Synchronous.php(25): File_ProcessUploadJob->perform()
#5 /home2/beloitm1/public_html/omeka15/application/libraries/Omeka/Job/Dispatcher/Default.php(95): Omeka_Job_Dispatcher_Adapter_Synchronous->send('{"className":"F...', Array)
#6 /home2/beloitm1/public_html/omeka15/application/models/File.php(70): Omeka_Job_Dispatcher_Default->send('File_ProcessUpl...', Array)
#7 [internal function]: File->afterInsert()
#8 /home2/beloitm1/public_html/omeka15/application/libraries/Omeka/Record.php(282): call_user_func_array(Array, Array)
#9 /home2/beloitm1/public_html/omeka15/application/libraries/Omeka/Record.php(561): Omeka_Record->runCallbacks('afterInsert')
#10 /home2/beloitm1/public_html/omeka15/application/libraries/Omeka/Record.php(581): Omeka_Record->save()
#11 /home2/beloitm1/public_html/omeka15/application/models/Item.php(303): Omeka_Record->forceSave()
#12 /home2/beloitm1/public_html/omeka15/application/models/Item.php(239): Item->saveFiles()
#13 [internal function]: Item->afterSave()
#14 /home2/beloitm1/public_html/omeka15/application/libraries/Omeka/Record.php(282): call_user_func_array(Array, Array)
#15 /home2/beloitm1/public_html/omeka15/application/libraries/Omeka/Record.php(566): Omeka_Record->runCallbacks('afterSave')
#16 /home2/beloitm1/public_html/omeka15/application/libraries/Omeka/Record.php(807): Omeka_Record->save()
#17 /home2/beloitm1/public_html/omeka15/application/libraries/Omeka/Controller/Action.php(419): Omeka_Record->saveForm(Array)
#18 /home2/beloitm1/public_html/omeka15/application/controllers/ItemsController.php(133): Omeka_Controller_Action->addAction()
#19 /home2/beloitm1/public_html/omeka15/application/libraries/Zend/Controller/Action.php(516): ItemsController->addAction()
#20 /home2/beloitm1/public_html/omeka15/application/libraries/Zend/Controller/Dispatcher/Standard.php(295): Zend_Controller_Action->dispatch('addAction')
#21 /home2/beloitm1/public_html/omeka15/application/libraries/Zend/Controller/Front.php(954): Zend_Controller_Dispatcher_Standard->dispatch(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http))
#22 /home2/beloitm1/public_html/omeka15/application/libraries/Zend/Application/Bootstrap/Bootstrap.php(97): Zend_Controller_Front->dispatch()
#23 /home2/beloitm1/public_html/omeka15/application/libraries/Zend/Application.php(366): Zend_Application_Bootstrap_Bootstrap->run()
#24 /home2/beloitm1/public_html/omeka15/application/libraries/Omeka/Core.php(165): Zend_Application->run()
#25 /home2/beloitm1/public_html/omeka15/admin/index.php(44): Omeka_Core->run()
#26 {main}

I don't really understand php, so any help with this issue would be greatly appreciated! I have several other instances of omeka running on the same server that do not have this problem.

The most important part of the log would be the line or two above "#0." That's where the actual error and message are.

Sorry. Above the code box, it says:

Omeka_File_Derivative_Exception
Something went wrong with image creation. Please notify an administrator.

Also, the error log in the admin directory shows this:

PHP Warning: Invalid argument supplied for foreach() in /home2/beloitm1/public_html/omeka15/application/models/Item.php on line 208

In order to trigger this error, I uploaded another couple of files. It's consistently working with tiny jpgs, but anything of a size is encountering the error.

Interesting wrinkle: it actually turns out that all my Omeka installations now have the same error (including 2.2). The 2.2 build spits out the additional error:

Omeka_File_Derivative_Exception
ImageMagick failed with status code 1. Error output:

libgomp: Thread creation failed: Resource temporarily unavailable

I assume something has gone funny with Bluehost's installation of Imagemagick, or the way Omeka plays with it. I will try to follow this up, but if anyone knows exactly what's wrong, I'd appreciate any help!