R help - Jul 2014 - SASxport function read.xport gives error "object 'w' not found"

The subject line says it. I've just tried converting an SAS .xpt file with 
this call:
   > read.xport( 'formats.xpt' )

I get the message
   Error in read.xport("formats.xpt") : object 'w' not found
but there's no explanation about what 'w' is or how I should make it
known
to R. I certainly wasn't expecting to have to provide such a variable, 
unless I've overlooked something in the SASxport documentation.

This is using R version 3.1.0 under Windows 7, and SASxport installed this 
morning: version 1.5.0 (2014-07-21).

Any idea what this 'w' is that read.xport wants me to give it?

The .xpt file is confidential, so I can't make it available, and I don't
know exactly what's in it. I suspect, however, that it may contain quite a 
bit of text. However, I'm pretty sure that its author used SAS correctly 
when generating it. Other files containing purely numeric data from the 
same author converted OK, using analogous calls to read.xport .

Googling the error didn't find anything.

Thanks,

Jocelyn Ireson-Paine
07768 534 091
http://www.jocelyns-cartoons.co.uk