crosstab help

I have a simple table
item_number week_of planned_qoh
------------------ ------------------ ------------------
00005 2012-02-05 30
00005 2012-02-12 40
00005 2012-02-19 50

where
item_number text
week_of date
planned_qoh integer

I have a function that returns the table as above:

chromasun._chromasun_totals(now()::date)

I want to see

00005 2012-02-05 2012-02-12 2012-02-19
30 40 50

This is what I have tried (although, I have tired many others)

select * from crosstab('select item_number::text as row_name,
to_char(week_of,''MM-DD-YY'') as bucket, planned_qoh::integer as buckvalue
from xchromasun._chromasun_totals(now()::date)')
as ct(item_number text, week_of date, planned_qoh integer)

I get
ERROR: return and sql tuple descriptions are incompatible

What am I doing wrong?

Johnf