When I am running a program which is for a web response I am getting a run time error as follows:
http: panic serving 127.0.0.1:43802: runtime error: invalid memory address or nil pointer dereference
goroutine 6 [running]:
net/http.(*conn).serve.func1(0xc4200a4a00)
/usr/lib/go-1.10/src/net/http/server.go:1726 +0x11b
panic(0x9b5360, 0xd99230)
/usr/lib/go-1.10/src/runtime/panic.go:502 +0x24a
github.com/ipfs/go-ipfs-api.(*RequestBuilder).Send(0xc4201740a0, 0xb95c60, 0xc420022100, 0x0, 0x0, 0x0)
The code of main file is as follows:
func main() {

router := httprouter.New()
router.RedirectTrailingSlash = true
c := cors.New(cors.Options{
	AllowedOrigins:   []string{"*"},
	AllowedMethods:   []string{"GET", "POST", "OPTIONS", "Authorization"},
	AllowedHeaders:   []string{"*"},
	AllowCredentials: true,
})
router.GET("/create", StoreAndGetHash)
router.GET("/read/:hashvalue", GetFile)
router.GET("/appdata/:appID", ReadPeer)
router.GET("/update", UpdateAndGetHash)
router.GET("/createdir", GetDir)
router.GET("/newkey", GetNewKey)

log.Fatal(http.ListenAndServe(":3000", c.Handler(router)))

}

I am working on ubuntu