Diagnosis
There is a profile variable with the name "abap/unicode_check",which is important for the question, wether all ABAP sources arerequired to fullfill the ABAP 6.10 Unicode enablement requirements.
The value of this profile parameter has to be "off" or "on
".

Procedure
Use report program RSPFPAR to check the value ofthe parameter. Use transaction RZ10 (profilemaintainance) to correct the value if neccesary. If you modify aprofile, the application server has to be restarted after that.