convert task failed

dear team

we have a conversion task in SSIS pacakge .

this task has been failing everytime with the error below.

"The output file name is empty."

here is the Advanced dynamic script.

(ON)

(INFILES,%INPUT_FILE%,"Import file:",)

(MESSAGE,"Load Transport cost from flat file")

(%TEMPFILE%,%TEMPPATH%%RANDOMFILE%)

(%SELECTIONFILES%,%TEMPPATH%%RANDOMFILE%)

(BPCAPPSET,%APPSET%)

(BPCSQLSERVER,%SQLSERVER%)

(SELECTIONFILE ,CONNECTIONSTRING ,%SELECTIONFILES%)

(SELECTIONFILE,%SELECTIONFILES%)

(INPUTFILE,%INPUT_FILE%)

(CONVERT,INPUTFILE,%SELECTIONFILES%)

(CONVERT,OUTPUTFILE,%TEMPFILE%)

(CONVERT,CONVERSIONFILE,%TRANSFORMATIONPATH%\\Transport_Cost\Transport_Cost.xls)

(CONVERT,STRAPPSET,%APPSET%)

(CONVERT,STRAPP,%APP%)

(CONVERT,STRUSERNAME,%USER%)

(DUMPLOAD,APPSET,%APPSET%)

(DUMPLOAD,APP,%APP%)

(DUMPLOAD,USER,%USER%)

(DUMPLOAD,DATATRANSFERMODE,4)

(DUMPLOAD,CLEARDATA,0)

(DUMPLOAD,FILE,%TEMPFILE%)

(DUMPLOAD,RUNTHELOGIC,0)

(DUMPLOAD,CHECKLCK,0)