I did these steps and i got that error, please can you help me about this:

S<-data$Stock

B<-data$Bond

taus<-seq(from = .05, to = .95, by = 0.05)

QR.coef <- coef(rq(S~B,tau=taus))

write.table(QR.coef, file = "QR.csv", sep = ",", col.names = NA, qmethod = "double")

lprq <- function(x, y, h, m=19 , tau=.5)

{

xx <- seq(min(x),max(x),length=m)

fv <- xx

dv <- xx

for(i in 1:length(xx)) {

z <- x - xx[i]

wx <- dnorm(z/h)

r <- rq(y~z, weights=wx, tau=tau, ci=FALSE)

fv[i] <- r$coef[1.]

dv[i] <- r$coef[2.]

}

data.frame(dv = dv)

}

QQR.coef <- as.data.frame(matrix(0, ncol = 19, nrow = 19))

for (i in 1:19){

x<-lprq(B,S,0.05,tau=taus[i])

QQR.coef[,i]<-x

}

Error in rq.fit.br(wx, wy, tau = tau, ...) : Singular design matrix