xj[i]中的错误:无效的下标类型“闭包”

I am getting this error when trying to run shiny application.

Error in xj[i] : invalid subscript type 'closure'


following are ui.R and server.R files.

ui.R
=========
visit = read.csv("lookuptable.csv",head=T) # reading table
shinyUI(pageWithSidebar(
  headerPanel('Disease Risk Prediction'),
  sidebarPanel(
    selectInput("patient",
                label = "Patient",
                choices = as.character(visit[,1]),
                selected = as.character(visit[1,1]),multiple = FALSE)

    ),
  mainPanel(
    plotOutput("plot1")  # plot bubble chart 
  )
))
server.R
==========
library(shiny)
shinyServer(
  function(input, output) {
    visit <- read.csv("lookuptable.csv",head=T)

    visit <- visit[1:39,1:22]

 ind   <- reactive({which(visit[,1]%in%input$patient)})
 prob <- reactive({as.numeric(visit[ind,c("prob1","prob2","prob3","prob4","prob5")])})
 time <- reactive({as.numeric(visit[ind,c("time1","time2","time3","time4","time5")])})
 icd <- reactive({visit[ind,c("icd1","icd2","icd3","icd4","icd5")]})
  icd <- reactive({apply(icd,2,as.character)})
I am getting this error when trying to run shin