Unable to schedule a maintenance order

HI

I created a maiantenance order via IP10. In IW32, when I click on the schdeuling icon, I get the message 'scheduling carried out..', but when I look at the operation > dates, the early & latest start dates are in the past are in the past (09/12/2011 & 14:55:00) and early start and finsh dates are 09/14/2011 (17:00:00). why is it not scheduling? Where are my basic & scheduled dates along with other information like sched type, rel date, etc?

In customising I set the scheduling type as backward, the contorl key is PM05 and has checked for everything and in the resource master data - in the capacity tab and other formula is SAP008 and schedling tab, other formula is SAP004 and capacity category is set for fintie sched, LTP, can be used in serveral operations.

In the task list, I maitained duration as 11 hrs and claculation key as 'manually', the work field is greyed out (why?), number = 1 etc.

I'm in ECC 6.0.

What else should I check? Pl. let me know.

Thanks

BE