[R] Confusing error statement

[Kurt_Helf at nps.gov]

Greetings
     Using the following command I've been trying to subset a dataframe of
counts of an organism to compute the sizes of groups for use as a
predictor:

Hs.patches <- as.data.frame(with(Hs.long,
      table(Cave,Year,Month,Region,Plot,)))

I am getting the following error message that I do not understand:

ERROR:  argument is missing, with no default

Can anyone shed light on this and suggest a possible fix?
Cheers
Kurt

***************************************************************
Kurt Lewis Helf, Ph.D.
Ecologist
EEO Counselor
National Park Service
Cumberland Piedmont Network
P.O. Box 8
Mammoth Cave, KY 42259
Ph: 270-758-2163
Lab: 270-758-2151
Fax: 270-758-2609
****************************************************************
Science, in constantly seeking real explanations, reveals the true majesty
of our world in all its complexity.
-Richard Dawkins

The scientific tradition is distinguished from the pre-scientific tradition
in having two layers.  Like the latter it passes on its theories but it
also passes on a critical attitude towards them.  The theories are passed
on not as dogmas but rather with the challenge to discuss them and improve
upon them.
-Karl Popper

...consider yourself a guest in the home of other creatures as significant
as yourself.
-Wayside at Wilderness Threshold in McKittrick Canyon, Guadalupe Mountains
National Park, TX

Cumberland Piedmont Network (CUPN) Homepage:
http://tiny.cc/e7cdx

CUPN Forest Pest Monitoring Website:
http://bit.ly/9rhUZQ

CUPN Cave Cricket Monitoring Website:
http://tiny.cc/ntcql

CUPN Cave Aquatic Biota Monitoring Website:
http://tiny.cc/n2z1o