but the new "Spaces in the Softimage install path" has come back to haunt us with missing plugins in the FX Tree...
One of the two solutions in this Knowledge Base Article is toIssue: In the Fx Operator Selector, the Plugins tab is empty (and in the Fx Tree, so is the Ops > Plugin menu).
.install Softimage 2011 in a location that does not include any spaces in the folder names.
And so we're back full circle: don't install Softimage in an install path that contains spaces...