samtools pileup output for SNP detection

[qtrinh]

Here is a link that describes the output of consensus and indels calling: http://samtools.sourceforge.net/cns0.shtml

[Mansequencer]

Hi All,
I aligned 50 bp solexa reads onto a reference genome using bowtie and now I am using samtools pileup -vcf to call SNPs. This is the output it generates:
scaffold179 29989 T A 30 30 60 1 A B
scaffold179 29991 A G 4 4 60 1 G #
scaffold179 29992 A T 4 4 60 1 T #
scaffold179 29993 T A 4 4 60 1 N #
scaffold179 29994 T A 4 4 60 1 N #
scaffold179 29995 A C 4 4 60 1 C #
scaffold179 29997 T A 4 4 60 1 N #
scaffold179 29998 G C 4 4 60 1 C #
scaffold179 29999 T C 4 4 60 1 C #
scaffold179 30000 T A 4 4 60 1 N #
scaffold179 30001 T A 4 4 60 1 A #
scaffold179 30002 G A 4 4 60 1 A #
scaffold179 30003 A G 4 4 60 1 G #
scaffold179 30004 T C 4 4 60 1 C #
scaffold179 30005 T A 4 4 60 1 A #
scaffold179 30006 T A 4 4 60 1 N #
scaffold179 30007 G A 4 4 60 1 N #
scaffold179 30008 T A 4 4 60 1 N #
scaffold179 30009 G A 4 4 60 1 N #
scaffold179 30010 T A 4 4 60 1 N #
scaffold179 30011 T A 4 4 60 1 N #
scaffold179 30012 T A 4 4 60 1 N #
scaffold179 30013 T A 4 4 60 1 N #
scaffold179 30014 G A 4 4 60 1 N #

I understand that columns from left to right are:
Scaffold name:
coordinate:
reference base:
polymorphic base:

I am confused about the numbers after the 4th column. Please suggest as to what they correspond to.
Also when I try to look at the alignment in tview, it shows only Ns after the first 80 pb. My reference genome does contain some short stretches of Ns but is not all Ns so why does the samtools tview shows only Ns?
Any suggestion would be highly appreciated.
Thanks for all the help.
Thanks.