Can somebody help me with my error pls?

Agent1 <- data.frame( AgentNo = 1,
                      State = "E",
                      Mixing = runif(1,0,1))

nPOP1 <- 10
# create a population of Agents

for(i in 2:nPOP1){
  Agent2 <- data.frame( AgentNo = i,
                        State = "S",
                        Mixing = runif(1,0,1))
  Agent1 <-rbind(Agent1, Agent2)
}

#Part 2
for (i in 1:nPOP1){
  #Determine if they like to meet others 
  Mix1 <- Agent1$Mixing [i ]
  # how many agents will they meet?
  Meet1 <- round(Mix1*3,0)
  # Grab the agents they will meet
  Meet2 <- sample( 1:nPOP1, Meet1, replace = TRUE)

  for( j in 1:length(Meet2)){
    #Grab who they will meet
    Meet1a <- Agent1[ Meet2[j], ]
    #If exposed change state
    if (Meet1a$State == "E" ) {
      Agent1$State [1] <- "E"
    }
  }
}



Error in if (Meet1a$State == "E") { : 
  missing value where TRUE/FALSE needed

What should i do with that?