Flat file creating error

Now, I making a file using convertostring service.

but some case of using convertostring ,

automatically replaced front string to schma Record name.

ex)

–Real data-
1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1

-Generated Data-
PID_OPEN 1 1 1 1 1
PID_OPEN 1 1 1 1 1
PID_OPEN 1 1 1 1 1

could you give a advice?

give more details on this …
1. what are the inputs specifying in the convertToString?
2. flatfile schema details…
record parser.
field parser.