[R] Estimate and plot hazard function using "muhaz" package

[Deming Mi]

Dear R users,
I am trying to use "muhaz" and "plot.muhaz" functions in "muhaz" package to 
estimate and plot hazard funciton.  However function "muhaz" always gives 
error message "Error in Surv(times, delta) : object "times" not found".  I 
could not even run their sample codes in the user's manual as follows:

data(ovarian)
attach(ovarian)
fit1 <- muhaz(futime, fustat)

it gave the same error message.  By the way, the "survival" package is 
installed and functions well on my computer.

Does anyone have the same problem?  Thanks!

Deming