Internal server error(500) for create_stream method in odata

below is my code, even though file is inserted into the database table still it is showing 500 internal server error, how to handle this error?

Can any one help on this.

Best regards,

Surekha

method /IWBEP/IF_MGW_APPL_SRV_RUNTIME~CREATE_STREAM.
data : ls type ZCL_ZNO_SESS_MPC_EXT=>TS_FILE.
ls-FILENAME = IV_SLUG.
ls-SYDATE = sy-DATUM.
ls-SYTIME = sy-UZEIT.
ls-MIMETYPE = IS_MEDIA_RESOURCE-MIME_TYPE.
ls-VALUE = IS_MEDIA_RESOURCE-VALUE.
insert INTO ZNO_FILE VALUES ls.
endmethod.