[R] ggplot2 will not draw a rectangle. Error: ggplot2 doesn't know how to deal with data of class XXX"

[John Kane]

What am I missing?  When I run the code below I get the error message
"Error: ggplot2 doesn't know how to deal with data of class function"

Googling suggests a message of "Error: ggplot2 doesn't know how to deal with data of class XXX" is not uncommon but I don't see why I am getting a "function" error unless I am using some reserved word?

##=============Start Code=========================
library(ggplot2)
  
  fcs  <-  structure(list(year = structure(c(954478800, 986014800, 1017550800, 
           1049086800, 1080709200, 1112245200, 1143781200, 1175313600, 1206936000, 
           1238472000, 1270008000, 1301544000, 1333166400), class = c("POSIXct", 
          "POSIXt"), tzone = ""), federal.ps = c(211925L, 223933L, 237251L, 
           242737L, 244158L, 243971L, 249932L, 254622L, 263114L, 274370L, 
           282955L, 282352L, 278092L)), .Names = c("year", "federal.ps"), 
           class = "data.frame", row.names = c(NA, -13L))
  
  
  p  <-  ggplot(fcs, aes(year, federal.ps )) + geom_line()
  
  p  +  geom_rect(data=rect, aes(xmin=xmin, xmax = xmax, ymin=-Inf, ymax = Inf), 
                  fill='red', alpha=0.2)
##=============End Code==========================

sessionInfo()
R version 2.15.3 (2013-03-01)
Platform: i686-pc-linux-gnu (32-bit)

locale:
 [1] LC_CTYPE=en_CA.UTF-8       LC_NUMERIC=C              
 [3] LC_TIME=en_CA.UTF-8        LC_COLLATE=en_CA.UTF-8    
 [5] LC_MONETARY=en_CA.UTF-8    LC_MESSAGES=en_CA.UTF-8   
 [7] LC_PAPER=C                 LC_NAME=C                 
 [9] LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=en_CA.UTF-8 LC_IDENTIFICATION=C       

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

other attached packages:
[1] ggplot2_0.9.3

loaded via a namespace (and not attached):
 [1] colorspace_1.2-1   dichromat_2.0-0    digest_0.6.3       grid_2.15.3       
 [5] gtable_0.1.2       labeling_0.1       MASS_7.3-23        munsell_0.4       
 [9] plyr_1.8           proto_0.3-10       RColorBrewer_1.0-5 reshape2_1.2.2    
[13] scales_0.2.3       stringr_0.6.2    


John Kane
Kingston ON Canada

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