For a parameterized build, the string parameter variable isn't expanded in the Branch field within the Source Code Management section. I have attached the config.xml for the job.

Error message when trying to build:

[TradeSheetV2-QA-Test] $ cvs -Q -z3 - d :pserver:utebuild@tradesheet.cvs.services.gs.com:/cvsroot/tradesheet co -P -r ${BUILDTAG} -d workspace tradesheet
cvs [checkout aborted]: no such tag ${BUILDTAG}
FATAL: CVS failed. exit code=1
Finished: FAILURE

The version we are using is 1.326 which is relatively old but I can't see in the release notes that this issue has been addressed since then.

Some background:

We have an application that manages our baselines and given a set of change sets it creates a tag on the whole system. The tag is fixed, i.e. different names each time, to reflect the version to be built, e.g. TS2_1_1_0_RC-2. We then start the Hudson job and it prompts for the tag. Hudson is then supposed to checkout the code using this tag.
In another project we use Ant to build and we have then been able to add a Shell script job that does the checkout rather than having Hudson do it. For this project we use Maven and from what I can see it doesn't allow more than one 'builder'. Using a builder (shell script) to do the checkout is a workaround anyway and not the prefered way to checkout from a tag given as a parameter.