Running examples in ‘gdm-Ex.R’ failed
The error most likely occurred in:

> base::assign(".ptime", proc.time(), pos = "CheckExEnv")
> ### Name: formatsitepair
> ### Title: Converts Common Biological (Response) and Environmental
> ###   (Predictor) Data Formats to a GDM Site-Pair Table
> ### Aliases: formatsitepair
> ### Keywords: gdm
> 
> ### ** Examples
> 
> 
> ##table data, species and environmental
> load(system.file("./data/gdm.RData", package="gdm"))
> sppData <- gdmExpData[, c(1,2,13,14)]
> envTab <- gdmExpData[, c(2:ncol(gdmExpData))]
> 
> ##environmental raster data
> ##commented out to reduce example run time
> #rastFile <- system.file("./extdata/stackedVars.grd", package="gdm")
> #envRast <- stack(rastFile)
> 
> #########table type 1
> ##site-species table without coordinates
> testData1a <- reshape2::dcast(sppData, site~species)
Using Long as value column: use value.var to override.
Aggregation function missing: defaulting to length
> ##site-species table with coordinates
> coords <- unique(sppData[, 2:ncol(sppData)])
> testData1b <- merge(testData1a, coords, by="site")
> ##site-species, table-table
> exFormat1a <- formatsitepair(testData1a, 1, siteColumn="site", XColumn="Long", YColumn="Lat",
+ 	predData=envTab)
> 
> ##site-species, table-raster
> ##not run
> #exFormat1b <- formatsitepair(testData1b, 1, siteColumn="site", XColumn="Long", YColumn="Lat",
> #	predData=envRast)
> 
> #########table type 2
> ##site xy spp list, table-table
> exFormat2a <- formatsitepair(sppData, 2, XColumn="Long", YColumn="Lat", sppColumn="species",
+ 	siteColumn="site", predData=envTab)
Warning in formatsitepair(sppData, 2, XColumn = "Long", YColumn = "Lat",  :
  No abundance column was specified, so the species data are assumed to be presences.
Aggregation function missing: defaulting to length
> ##site xy spp list, table-raster
> ##commented out to reduce example run time
> #exFormat2b <- formatsitepair(sppData, 2, XColumn="Long", YColumn="Lat", sppColumn="species",
> #	siteColumn="site", predData=envRast)
> 
> #########table type 3
> ##dissim matrix model
> site <- unique(sppData$site)
> gdmDissim <- cbind(site, gdmDissim)
> exFormat3 <- formatsitepair(gdmDissim, 3, XColumn="Long", YColumn="Lat", predData=envTab,
+ 	siteColumn="site")
Error in xtfrm.default(x) : cannot xtfrm 'x'
Calls: formatsitepair ... lapply -> FUN -> as.vector -> xtfrm -> xtfrm.default
Execution halted