Item Images Won't Display

Note: When I tried to add new information to the bottom of my first post, the system notified me that the topic had been closed. It's not resolved, so I don't know why; I didn't get any responses. Please let me know if I'm misusing the forum?
Thanks.

Begin initial post:

Hi,

I am a newbie, trying to upload items for the first time. When I attach image files to an item, they won't display, either at the top of the item page or on the side (where I think they'd appear as thumbnails if all were well). The side display contains little squares where the thumbnails should be (see http://archiveofchildhood.com/items/show/1), but when I click on one, I get the following error message:

Omeka has encountered an error
Zend_Controller_Dispatcher_Exception
Invalid controller specified (archive)

Backtrace
exception 'Zend_Controller_Dispatcher_Exception' with message 'Invalid controller specified (archive)' in /nfs/c07/h02/mnt/101667/domains/archiveofchildhood.com/html/application/libraries/Zend/Controller/Dispatcher/Standard.php:248
Stack trace:
#0 /nfs/c07/h02/mnt/101667/domains/archiveofchildhood.com/html/application/libraries/Zend/Controller/Front.php(954): Zend_Controller_Dispatcher_Standard->dispatch(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http))
#1 /nfs/c07/h02/mnt/101667/domains/archiveofchildhood.com/html/application/libraries/Zend/Application/Bootstrap/Bootstrap.php(97): Zend_Controller_Front->dispatch()
#2 /nfs/c07/h02/mnt/101667/domains/archiveofchildhood.com/html/application/libraries/Zend/Application.php(366): Zend_Application_Bootstrap_Bootstrap->run()
#3 /nfs/c07/h02/mnt/101667/domains/archiveofchildhood.com/html/application/libraries/Omeka/Core.php(166): Zend_Application->run()
#4 /nfs/c07/h02/mnt/101667/domains/archiveofchildhood.com/html/index.php(30): Omeka_Core->run()
#5 {main}

Any ideas?
Thanks in advance.

Rebecca

Additional information:

Update: I've been looking over all of the past forum threads, and I wonder if this "Zend" error message might have something to do with the error I received when I initially installed Omeka:

"Fileinfo Module Not Loaded: Without the fileinfo module loaded into PHP, the content type and encoding of uploaded files cannot be read. The installer will disable file upload validation."

I'm using PHP 5.2.17. I just opened a support ticket with my host, to see if they can help.

If anybody knows whether this Zend error is related, I'd appreciate hearing about it - if it's a whole other issue, I may have more to fix than I thought I did.

Thanks.
Rebecca

The Zend error about "invalid controller specified" is definitely a sign of a problem.

That message indicates either a problem with your .htaccess file, or a problem that's causing your files not to be saved in the archive.

If you look in your installation's archive folder, are there any files inside the subfolders "files" or "thumbnails"?

The Fileinfo error probably isn't related: we display that message to tell you that Omeka won't be attempting to validate the file types of the files you're uploading.