[R-sig-Geo] Error with RGEOS

[Sancta Vega]

Just for dissolving I use the rgeos package with gUnaryUnion. But I get
this error :No UnaryUnion in this version of GEOS. I remove the package and
install it again but I get the same error. Is it linked to my version of R
or something else? This my code:

     require("rgeos")
     summary(utah) #
     regional= gUnaryUnion(utah,utah$region)


According to your suggestion I ask my question with more details:

For my R version:
R version 3.0.2 (2013-09-25) -- "Frisbee Sailing"
Copyright (C) 2013 The R Foundation for Statistical Computing
Platform: i686-pc-linux-gnu (32-bit)


>From library (rgeos) I get this warning :
rgeos version: 0.3-6, (SVN revision 450)
 GEOS runtime version: 3.2.2-CAPI-1.6.2
 Polygon checking: TRUE


Thank you

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