IOError: [Errno 32] Broken pipe

[Jay Donnell]

I'm working on a simple script to manipulate csv files. Right now it
just prints the first field of the file for each line. Everything
works fine, but if I use 'head' or 'more' and quit while in more then
I get
IOError: [Errno 32] Broken pipe

Anyone know why this is happening?

jay at linux:~/Desktop/gmProductData> ./variance.py | head
91109 : 91109
A0101 : A0101
A0102 : A0102
A0103 : A0103
A0104 : A0104
A0105 : A0105
A0106 : A0106
A0107 : A0107
A0111 : A0111
A0112 : A0112
Traceback (most recent call last):
  File "./variance.py", line 39, in ?
    print '%s : %s' % (match, skuS[0])
IOError: [Errno 32] Broken pipe