[R-sig-Geo] Error using gpclib fuctions

[Breitbach, Nils]

Dear Community,

trying to get through the examples from "Applied Spatial Data Analysis with R" I got problems with the gpclib package. 

The library was loaded correctly:

> library(gpclib)
General Polygon Clipper Library for R (version 1.5-1)
	Type 'class ? gpc.poly' for help

... but then when I tried to use the unionSpatialPolygons function I recieved the following error message:

> nc90.temp_spndf <- unionSpatialPolygons(nc90_spndf, IDs = paste(nc90_spndf$ST, nc90_spndf$CO, sep="_"))
Error: isTRUE(gpclibPermitStatus()) is not TRUE

I am aware that GPC is not generally free but free for academic research, which is hopefully what I am doing here. Do I have to place a licence file somewhere to satisfy the gpclibPermitStatus function? Or do I need to install the GPC software in addition to the package?

Cheers,

Nils Breitbach