Marmotta 3.3.0 - SPARQL - SUM

[Fabian Cretton]

Hi,
 
Is SPARQL-sum implemented in the current version under developpment (3.3.0) ?
 
I did refresh my fork two weeks ago, and this query doesnt' work:
 
prefix sdmx-measure: <http://purl.org/linked-data/sdmx/2009/measure#>
SELECT (SUM(?value) as ?valSum) WHERE {
  ?obs sdmx-measure:obsValue ?value.
}
 
I have an error message in the interface: unknown exception while evaluating 
SPARQL query
 
I can't see the logs right now (I have to check out why my logs no more work 
since my last synchronisation)
 
But is "sum" implemented or not ? or maybe I do have a simple syntax mistake ?
 
thank you for any help
Fabian