Hi Greger,
While generating extract str at BW01, have you selected total records or line item check box there?
Once you generate extract str, have you got status bar message like extract str was generated?
Seems like there is ledgers at your source side. please check about it.
Even about ledger and table types all settings are done by FI team. is they done before this?
Is this is fresh or new system? if yes then seek FI team help.
Once FI team maintain required ledgers later you can do generation of data source.
Thanks