This may be a red herring, but when you contact tech support, you should also tell them that there was a very, very similar bug that was fixed in version 10.0 but for the SDE Java API. I looked at the fix and the same issue is not apparent to me in the C API code--which is why it might not be the same bug.
Reference NIM040332: Running SeQuery.createTableStatistics with the 'SeTable.SeTableStats.SE_DISTINCT_STATS' option hangs when processing an nvarchar field from an ArcSDE 9.2 SQL Server 2005 database and gives an error when processing an nvarchar2 field from an ArcSDE 9.2 Oracle database.
Do you compile with SDE_UNICODE enabled (SE_WCHAR parameters) or not?
That leaves you with two options -- Using SE_STRING_TYPE columns
You should certainly contact Tech Support (and have them contact me for sample code to demonstrate the problem).
Okay, please do not consider this a binding/legal Esri answer, but going by the ArcGIS for Server Product life cycle document, 10.0 is in mature support while 10.1 is still in extended support. Further information on what that means is available here.
SELECT count(colname) cnt,colname FROM tablename GROUP BY colname ORDER BY colname