Code is VERY lengthy, but here are the pieces involving the problem.

LPARAMETERS tcDatabase,tcTable
*-- Note:
*-- tcDatabase = "AS-400DispensingData"
*-- tcTable = "Non_Formulary_Data" as passed in

*-- several LOCAL variable declarations

lcTable=LOWER(IIF(EMPTY(tcTable),ALIAS(),ALLTRIM(tcTable)))

lcDBF=lcTable
lcAlias=LOWER(SYS(2015))
IF !EMPTY(tcDatabase) AND FILE(tcDatabase)
OPEN DATABASE (tcDatabase)
ENDIF FILE(tcDatabase)
IF FILE(lcDBF)
SELECT 0
USE (lcDBF) ALIAS (lcAlias) AGAIN SHARED
ENDIF

Error is "Alias Non_Formulary_Data not found"; however, I had already opened and closed it earlier in the same routine.