ggmap doesn't show maps

Question

I have the following code:

library(ggmap) 
ggmap(get_map(location=c(lon = 5.218922, lat = 52.342366), zoom =14))

Which by my account should work fine, but I only get a standard ggplot2 image (grey background, etc), with the correct axis, but without the map shown:

When I look in my working directory I do find a file called "ggmapTemp" which has the correct map in it. But the map is not shown by ggplot2.

I work with RStudio and have limited rights on my work pc. Could this be the reason that the map is not shown correctly? My version of RStudio is 0.96.316 and R is R-2.15.1.

> sessionInfo()
 R version 2.15.1 (2012-06-22)
 Platform: x86_64-pc-mingw32/x64 (64-bit)

 locale:
 [1] LC_COLLATE=Dutch_Netherlands.1252  LC_CTYPE=Dutch_Netherlands.1252   
 [3] LC_MONETARY=Dutch_Netherlands.1252 LC_NUMERIC=C                      
 [5] LC_TIME=Dutch_Netherlands.1252    

 attached base packages:
 [1] stats     graphics  grDevices utils     datasets  methods   base     

 other attached packages:
 [1] ggmap_2.1     ggplot2_0.9.1

 loaded via a namespace (and not attached):
 [1] colorspace_1.1-1   dichromat_1.2-4    digest_0.5.2       grid_2.15.1       
 [5] labeling_0.1       MASS_7.3-18        memoise_0.1        munsell_0.3       
 [9] plyr_1.7.1         png_0.1-4          proto_0.3-9.2      RColorBrewer_1.0-5
 [13] reshape2_1.2.1     RgoogleMaps_1.2.0  rjson_0.2.9        scales_0.2.1      
 [17] stringr_0.6        tools_2.15.1   

Update: My sessionInfo() after answer 1:

sessionInfo()

 attached base packages:
 [1] stats     graphics  grDevices utils     datasets  methods   base     

 other attached packages:
 [1] mapproj_1.1-8.3 maps_2.2-6      ggmap_2.1       ggplot2_0.9.1  

 loaded via a namespace (and not attached):
 [1] colorspace_1.1-1    dichromat_1.2-4     digest_0.5.2        grid_2.15.1        
 [5] labeling_0.1        MASS_7.3-20         memoise_0.1         munsell_0.3        
 [9] plyr_1.7.1          png_0.1-4           proto_0.3-9.2       RColorBrewer_1.0-5 
 [13] reshape2_1.2.1      RgoogleMaps_1.2.0.2 rjson_0.2.9         scales_0.2.1       
 [17] stringr_0.6.1       tools_2.15.1  

As requested:

capabilities()
jpeg      png     tiff    tcltk      X11     aqua http/ftp  sockets   libxml     fifo 
TRUE     TRUE     TRUE     TRUE    FALSE    FALSE     TRUE     TRUE     TRUE    FALSE 
cledit    iconv      NLS  profmem    cairo 
TRUE     TRUE     TRUE     TRUE     TRUE 

Answer 1

On my machine, the list of attached packages is:

other attached packages:
[1] mapproj_1.1-8.3 maps_2.2-6      ggmap_2.1       ggplot2_0.9.1  

This means you probably need mapproj as well as maps to run your code, since these are suggested packages from ggplot to enable correct map projections.

Try:

install.packages(c("mapproj", "maps"))

then rerun your code.