there are a number of problems with the page you have sent:
1) you will not be able to use the Dreamweaver Insert Behavior to store the uploaded file name to your database.This can only be done using the Data Assist Insert / Update record behavior.
File upload works like this:
the form sends the file to server
the server saves that file to upload folder you specify and performs any necessary renaming of the uploaded file if it already exists, or other formatting based on your settings in the upload wizard.
the file name is saved in a variable that has a binding in the bindings panel under WA Uploaded Files (File Field Name) -> Server File Name
The limitation to the Dreamweaver Insert / Update record behavior is that it can only use form elements to get information to store, it cannot access the server file name variable that the upload creates, this is why Data Assist must be used instead.
2) The upload code references a file field named "AvailFile2" but yours is named "AvailFile"
<input type="file" name="AvailFile" id="AvailFile" />
this is the same name as a hidden form element on your page:
<input type="hidden" name="AvailFile" value="<?php echo htmlentities($row_rsAvail['AvailFile'], ENT_COMPAT, 'utf-8'); ?>" size="32" />
all form elements must use a unique name.
3) for file upload to work properly, the form encoding type must be set to multipart/for-data.
in the tag selector, select the form tag, in the encoding type select list, select multipart/form-data