Upload / Attach Issue in 7018

Upload / Attach Issue in 7018

Just installed ServiceDesk 7018. Users are reporting that attaching a file to a request gives a javascript error and doesn't upload the file.

Steps to reproduce:
Click "New Request"
Click "Attach File" button
Browse to a File
Click "Attach File" button

User gets a Javascript error:
Line 48
Char 1
Error: Object doesn't support this property or method
URL: <removed> /common/FileAttachment.jsp

Anyone else experiencing this, and any ideas on resolution? We have one group of technicians that gets small file attachments frequently, so this has essentially got us stopped.