I don't know if this will help. but I have gotten that error message when calling stored procs with variables that go out of scope. For example:

local cMyVar
cMyVar='STRING'
SP_MYSTOREDPROC(@cMyVar)

gives that exact error while

private cMyVar
cMyVar='STRING'
SP_MYSTOREDPROC(@cMyVar)

works

Maybe there is a clue in this?

Mike