Damian --
I believe you will find that the Spooler message is being caused by a local
resource which the PM has entered in the project plan. A local resource is
a resource that is not found in the Enterprise Resource Pool and does not
have a Project Server account, and is unique to this project only. This
resource will be indicated as "local" by its indicator in the Indicators
column of the Resource Sheet view. The indicator for this resource should
be a single head with a piece of paper to the left of it. The error message
is being generated by Microsoft Project trying to create a Project Server
account for this resource, but permissions are set in PWA to deny the
creation of accounts by the project manager.
To solve this issue, I would recommend that you have the PM change this
local resource to a local Generic resource. To do so, have the PM
double-click on the resource name in the Resource Sheet view, check the
"Generic" option, and then click OK. The next time the PM publishes this
project, he/she will not generate the Spooler error because Microsoft
Project does not create accounts for Generic resources. Hope this helps.