I think what happens is the following:
When you boot local from CD/DVD you should see 2 drives.
X: - RAM DISK OS (PE, based on BOOT.WIM in sources folder on CD/DVD
Y: - Full content of the CD/DVD - including the sources folder and programs folder on the CD/DVD. Drive Y is assigned based on a tag file on the CD/DVD I think.
By default, most of the tools are not embedded into the RAM DISK (boot.wim), but are located in the programs folder on the CD/DVD (plugin option "RUN from CD")
When you boot over network, you will only see drive X: (RAMDISK OS based on sources\boot.wim) as described above. As the CD/DVD itself is not available after boot to the machine, you wont have drive Y -> hence you are
missing the programs folder and therefore all the programs located outside the RAMDISK will not be availalbe.
What you could do is use the plugin's option to "RUN FROM RAM". This will put the files into the RAMDISK instead of the programs folder. However, this will increase the BOOT.WIM size and there are limits in how big that file can be when booting over the network I think... May be others have better ideas.