[R] Error in merge [negative length vectors are not allowed]

[Kate Ignatius]

Hi All,

I'm trying to merge two files together using:

combinedfiles <- merge(comb1,comb2,by=c("Place","Stall","Menu"))

comb1 is about 2 million + rows (158MB) and comb2 is about 600K+ rows (52MB).

When I try to merge using the above syntax I get the error:

Error in merge.data.frame(comb1, comb2, by = c("Place","Stall","Menu")) :
  negative length vectors are not allowed

Is there is something that I'm doing wrong?  I've merged larger files
together in the past without a problem so am curious what might be the
problem here...

Thanks in advance!

~K