OK, so I've trawled thought the other collector errors posted, but to no avail...
It's a new install, the web panel connects to the VCenter server OK, but keeps failing upon collection.
Here is the error. Any pointers greatfully recieved. 
A collection from x.x.x.x, begun at 2012-05-15 11:35:05, failed at
2012-05-15 11:35:06.
Usage Meter will abandon collecting from this vCenter Server until the
next collection cycle.
java.util.concurrent.ExecutionException:
java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:222)
java.util.concurrent.FutureTask.get(FutureTask.java:83)
com.vmware.cloud.usgmtr.commons.Parallelizer$anonfun$3.apply(Parallelizer
.scala:22)
com.vmware.cloud.usgmtr.commons.Parallelizer$anonfun$3.apply(Parallelizer
.scala:22)
scala.collection.TraversableLike$anonfun$map$1.apply(TraversableLike.scal
a:194)
scala.collection.TraversableLike$anonfun$map$1.apply(TraversableLike.scal
a:194)
scala.collection.Iterator$class.foreach(Iterator.scala:660)
scala.collection.immutable.VectorIterator.foreach(Vector.scala:621)
scala.collection.IterableLike$class.foreach(IterableLike.scala:73)
scala.collection.immutable.Vector.foreach(Vector.scala:36)
scala.collection.TraversableLike$class.map(TraversableLike.scala:194)
scala.collection.immutable.Vector.map(Vector.scala:36)
com.vmware.cloud.usgmtr.commons.Parallelizer$.run(Parallelizer.scala:22)
com.vmware.cloud.usgmtr.collect.vc.VCenterCollector.collect(VCenterCollect
or.scala:53)
com.vmware.cloud.usgmtr.collect.VCenterCollectorCaller.<init>(VCenterColle
ctorCaller.scala:20)
com.vmware.cloud.usgmtr.collect.Collector$.collectAndSaveSamples(Collector
.scala:71)
com.vmware.cloud.usgmtr.collect.Collector$.collectAndSaveSamples(Collector
.scala:99)
com.vmware.cloud.usgmtr.collect.Collector$.collectAndSaveSamples(Collector
.scala:99)
com.vmware.cloud.usgmtr.collect.Collector$anonfun$collectAll$2$anonfun$a
pply$1.apply$mcV$sp(Collector.scala:30)
com.vmware.cloud.usgmtr.collect.Collector$anonfun$collectAll$2$anonfun$a
pply$1.apply(Collector.scala:29)
com.vmware.cloud.usgmtr.collect.Collector$anonfun$collectAll$2$anonfun$a
pply$1.apply(Collector.scala:29)
org.squeryl.dsl.QueryDsl$class._using(QueryDsl.scala:46)
org.squeryl.dsl.QueryDsl$class._executeTransactionWithin(QueryDsl.scala:11
4)
org.squeryl.dsl.QueryDsl$class.transaction(QueryDsl.scala:78)
org.squeryl.PrimitiveTypeMode$.transaction(PrimitiveTypeMode.scala:40)
com.vmware.cloud.usgmtr.collect.Collector$anonfun$collectAll$2.apply(Coll
ector.scala:28)
com.vmware.cloud.usgmtr.collect.Collector$anonfun$collectAll$2.apply(Coll
ector.scala:28)
com.vmware.cloud.usgmtr.commons.Parallelizer$anonfun$2$anon$1.call(Paral
lelizer.scala:18)
java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
java.util.concurrent.FutureTask.run(FutureTask.java:138)
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.
java:886)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java
:908)
java.lang.Thread.run(Thread.java:662)