> any help would be greatly appreciated, thank you.

Try to lower the number of connection per second ("Set Options => Flow Control
=> Number of connections" to "1" and "Set Options => Limits => Max connections
/ seconds" to 0.5), and lower the transfer rate ("Set Options => Limits => Max
transfer rate" to 1000B/s -- you may raise this value in a second try), and
see if you grab more pages. Try also to disable cookies ("Set Options =>
Spider => Accept cookies" unchecked).

If not, the protection must be within invisible "link traps", which are
grabbed by offline browsers like httrack, triggering the blocking.

Anyway protections that prevent authors from downloading their work are a bit
strange - don't you have any ftp access to the server, or access to the
database ?