fastbw question

Hello

I am running R 2.0.1 on Windows, I am attempting to use Frank Harrell's
'fastbw' function (from the Design library), but I get an error that the
fit was not created with a Design library fitting function; yet when I
go to the help for fastbw (and also look in Frank's book Regression
Modeling Strategies) it appears that fastbw should work with a model
created with lm.....

Relevant code
<<<<<
model.borrow.logols<- lm(logborrow~age + sex + racgp + yrseduc + 
 needlchg + gallery  + totni + inject + poly(year.of.int,3)  + druginj
+ inj.years  + HTLV3)

fastbw(model.borrow.logols)

Thanks in advance


Peter

Peter L. Flom, PhD
Assistant Director, Statistics and Data Analysis Core
Center for Drug Use and HIV Research
National Development and Research Institutes
71 W. 23rd St
www.peterflom.com
New York, NY 10010
(212) 845-4485 (voice)
(917) 438-0894 (fax)