Package 'MASS' (polr): Error in svd(X) : infinite or missing values in 'x'

Hello,

I am trying to run an ordinal logistic regression (polr) using the package
'MASS'.

I have successfully run other regression classes (glm, multinom) without
much problem, but with the 'polr' class I get the following error:
" Error in svd(X) : infinite or missing values in 'x' "
which appears when I run the "summary" command.

The data file is large (585000 rows) and has no NA, -9999 or blank values.

My script (in brief) is as follows, with results:

############

library(MASS)

## ADD DATA
Jdata<- read.delim("/Analysis/20120709 JLittle data file.txt", header=T)

attach(Jdata)
names(Jdata)

[1] "POINTID"     "Lat_Y_pos"   "JVeg5"       "Subregion"   "Rock_U_Nam" 
"Rock_Name"   "Elevation"   "Slope"       "Aspect"      "Hillshade"  
"Stream_dist" "Coast_dist"  "Coast_SE"   
[14] "Coast_E"     "Wind_310"    "TPI"         "Landform"

Global <- polr(JVeg5 ~  Elevation +  Lat_Y_pos + Coast_dist + Stream_dist,
data=Jdata)

summary(Global)

Error in svd(X) : infinite or missing values in 'x'

##Try with omit NA command

Global <- polr(JVeg5 ~  Elevation +  Lat_Y_pos + Coast_dist + Stream_dist,
data=Jdata, na.action = na.omit, Hess = TRUE)

summary(Global)

Error in svd(X) : infinite or missing values in 'x'
############

Does this imply an 'infinite value' and what would this mean?

If anyone has any idea how to address this error, I would very much
appreciate your response.

Thank you in advance.

Jeremy

Date File Attachment (200 rows):
http://r.789695.n4.nabble.com/file/n4635829/20120709_JLittle_data_file.txt
20120709_JLittle_data_file.txt 


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