I apologize, in advance, for cross-posting this to the R listserv. I have submitted this query twice to the S listserv (yesterday and this morning)and neither post has "made it", not sure why. When I run the code gls.1 <- gls(y ~ x, data = foo.frame, weights = varPower(form = ~ fitted(.)|group), control = list(maxIter = 500, msMaxIter = 500), verbose = TRUE) I get the message "Warning messages: a database with name "controlvals" already in search list: access by where="controlvals" may not work in: attach(controlvals)" and Splus tells me that "Maximum number of iterations reached without convergence". What''s going on? I don''t remember ever attaching a database named "controlvals". Respectfully & Much Thanks in Advance, David Paul