Dissolve polygons - unionSpatialPolygons - Error : isTRUE(gpclibPermitStatus()) is not TRUE

Hi all,

I am trying to merge ICES divisions polygons by subareas i.e. division  
IVa, IVb and IVc in the shapefile and I want to obtain IV (IVa+IVb+IVc).

To realize that I thought to use the function unionSpatialPolygons().  
Is that a good choice?

If yes, I tried to apply it and obtained the error  
"isTRUE(gpclibPermitStatus()) is not TRUE".

I therefore try to find more information about the use of this  
function and download the following example:  
http://www.nceas.ucsb.edu/scicomp/usecases/PolygonDissolveOperationsR


Unfortunately I get the same error and I really don't understand how  
it coudl be as I am using the example script. Maybe something is wrong  
with my R configuration?

Thank you very much for your help,

Best,

Xochitl C.

R.Version()
$platform
[1] "i386-w64-mingw32"

$arch
[1] "i386"

$os
[1] "mingw32"

$system
[1] "i386, mingw32"

$status
[1] ""

$major
[1] "2"

$minor
[1] "15.3"

$year
[1] "2013"

$month
[1] "03"

$day
[1] "01"

$`svn rev`
[1] "62090"

$language
[1] "R"

$version.string
[1] "R version 2.15.3 (2013-03-01)"

$nickname
[1] "Security Blanket"