Getting error while exporting realm file

Tring to export realm file from below link given on keycloak site.

Getting below error,

keycloak@e78:/opt/bitnami/keycloak/bin$ kc.sh export --file D:\checkRealm.json
Appending additional Java properties to JAVA_OPTS: ‘-Djdk.security.allowNonCaAnchor=true’
ERROR: transport error 202: bind failed: Address already in use
ERROR: JDWP Transport dt_socket failed to initialize, TRANSPORT_INIT(510)
JDWP exit error AGENT_ERROR_TRANSPORT_INIT(197): No transports initialized [src/jdk.jdwp.agent/share/native/libjdwp/debugInit.c:744]