`sheetCount` and `sheetNames` fail when using R package gdata
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Problem: helpers fail when reading an .xls into R using gdata

I have some .xls that i'd like to read into R.  I am able to do so using `read.xls` in the `gdata` package, however the helper functions `sheetNames` and `sheetCount` fail - i'd like to understand what i'm doing wrong so that i can use them as they would be very useful. 

    require(gdata)
    fp <- file.path('~/data/first.xls')

When i know the structure of the sheets, and am able to point it at my intended data sheet, the perl script runs just fine: 

    firstdata <- read.xls(fp, sheet=2)

and i have my data... in `firstdata`. 

However, in the very same sheets, the helpers fail. 

I find myself opening the .xls in excel, figuring them out, and then loading into R using `read.xls(fp, sheet=N)` -- not a disaster, but neither is it ideal. 

In particular, when the sheets are not my own, and I need information about them before i can set `sheet=N` in `read.xls()`, the helper functions `sheetNames` and `sheetCount` would be very useful, however they fail -- why?  

    sheetCount(fp)

    > sheetNames(fp)
    Error in read.table(tc, as.is = TRUE, header = FALSE) : 
      no lines available in input
    In addition: Warning message:
    running command ''/usr/bin/perl'     '~/R/wd/raRpackages/gdata/perl/sheetNames.pl' '~/data/first.xls'' had status 2 
    Unable to open file '~/data/first.xls'.

and:

    > sheetCount(fp)
    Error in read.table(tc, as.is = TRUE, header = FALSE) :  
      no lines available in input
    In addition: Warning message:
    running command ''/usr/bin/perl'     '~/R/wd/raRpackages/gdata/perl/sheetCount.pl' '~/data/first.xls'' had status 2 
    Unable to open file '~/data/first.xls'.

I have double checked, and excel isn't open, and no other programs are using first.xls

thanks