Why doesn't my balance sheet balance?

i have to create a balance sheet out of the following data:

it was organised on 1 january 2010. at the end of january 2010, the following monthly financial data are available:

total revenues $150 000

total expenses (excl income tax) 100 000

income tax expense (all unpaid as of January 2010) $15 000

cash balance, 31 january 2010 $20 000

receivables from customers (all considered collectable) 25 000

merchandise inventory (by inventory count- at cost) 42 000

payables to suppliers for merchandise purchased from them (will be paid during Feb 2010) 11 000

contributed capital (2600 shares) 26 000

(no divends were declared or paid)

i put down cash, customer receivables and merchandise inventory under assets, payables to suppliers and income taxes under liabilites, and contributed capital under shareholder's equity.. but it doesn't balance.. can someone help me?