Running examples in 'rgeos-Ex.R' failed
The error most likely occurred in:

> ### Name: gBuffer
> ### Title: Buffer Geometry
> ### Aliases: gBuffer RGEOSBuffer
> ### Keywords: spatial
> 
> ### ** Examples
> 
> 
> p1 = readWKT("POLYGON((0 1,0.95 0.31,0.59 -0.81,-0.59 -0.81,-0.95 0.31,0 1))")
> p2 = readWKT("POLYGON((2 2,-2 2,-2 -2,2 -2,2 2),(1 1,-1 1,-1 -1,1 -1,1 1))")
> 
> par(mfrow=c(2,3))
> plot(gBuffer(p1,width=-0.2),col='black',xlim=c(-1.5,1.5),ylim=c(-1.5,1.5))
> plot(p1,border='blue',lwd=2,add=TRUE);title("width: -0.2")
> plot(gBuffer(p1,width=0),col='black',xlim=c(-1.5,1.5),ylim=c(-1.5,1.5))
> plot(p1,border='blue',lwd=2,add=TRUE);title("width: 0")
> plot(gBuffer(p1,width=0.2),col='black',xlim=c(-1.5,1.5),ylim=c(-1.5,1.5))
> plot(p1,border='blue',lwd=2,add=TRUE);title("width: 0.2")
> 
> plot(gBuffer(p2,width=-0.2),col='black',pbg='white',xlim=c(-2.5,2.5),ylim=c(-2.5,2.5))
> plot(p2,border='blue',lwd=2,add=TRUE);title("width: -0.2")
> plot(gBuffer(p2,width=0),col='black',pbg='white',xlim=c(-2.5,2.5),ylim=c(-2.5,2.5))
> plot(p2,border='blue',lwd=2,add=TRUE);title("width: 0")
> plot(gBuffer(p2,width=0.2),col='black',pbg='white',xlim=c(-2.5,2.5),ylim=c(-2.5,2.5))
> plot(p2,border='blue',lwd=2,add=TRUE);title("width: 0.2")
> 
> p3 <- readWKT(paste("GEOMETRYCOLLECTION(",
+  "POLYGON((0 1,0.95 0.31,0.59 -0.81,-0.59 -0.81,-0.95 0.31,0 1)),",
+  "POLYGON((2 2,-2 2,-2 -2,2 -2,2 2),(1 1,-1 1,-1 -1,1 -1,1 1)))"))
> 
> par(mfrow=c(1,1))
> plot(gBuffer(p3, byid=TRUE, width=c(-0.2, -0.1)),col='black',pbg='white',
+ xlim=c(-2.5,2.5),ylim=c(-2.5,2.5))
> plot(p3,border=c('blue', 'red'),lwd=2,add=TRUE);title("width: -0.2, -0.1")
> library(sp)
> p3df <- SpatialPolygonsDataFrame(p3, data=data.frame(i=1:length(p3),
+  row.names=row.names(p3)))
> dim(p3df)
[1] 2 1
> row.names(p3df)
[1] "1" "2"
> dropEmpty = gBuffer(p3df, byid=TRUE, id=letters[1:nrow(p3df)], width=c(-1, 0))
Error in (function (classes, fdef, mtable)  : 
  unable to find an inherited method for function 'row.names<-' for signature '"data.frame", "character"'
Calls: gBuffer -> row.names<- -> <Anonymous>
Execution halted