[R] R 2.8.1 and 2.9 alpha crash when running survest of Design package

[Terry Therneau]

A couple additions to Thomas's message.

  The 'survest' function in design directly called C routines in the survival 
package.  The argument list to the routines changed due to the addition of 
weights; calling a C routine with the wrong arguments is one of the more 
reliable ways to crash a program.  The simplest (short term) solution is to use 
survfit for your curves rather than survest.  Frank Harrell has been aware of 
the issue for several weeks and is working hard on solving it.  The simple fix 
is a few minutes, but he's thinking about how to avoid any future problems.  The 
C routines in survival change arguments VERY rarely, but direcly calling the 
routines of another package is considered dangerous in general.
  
  Most breakage was less severe.  For instance there were a couple of errors in 
the PBC data set.  I fixed these, and also replaced all the "999" codes with NA 
to make it easier to use.  Some other packages use this data.  (My name is on 
most of the PBC papers and I have the master PBC data with all labs, patient id, 
etc, but I was not the source of the first data set).  
  
  We'll be keeping an eye on the R list as the package rolls out; sending a 
message directly to Thomas and/or I would also be appreciated for issues like 
this.
  
  	Terry Therneau