Unable to transport Datasources in R/3

Can anyone help me with transporting datasources:

I have transferred (activated) some datasources in SD in our R/3 system. Then i have chosen the option to 'transport datasource'. Nothing happens. When i have done this before, I was able to allocate the datasource to a transport request and have it transported through to our QA and Production systems.

I have allocated the datasource to a development class ZBWD through the object directory, (R3TR OSOA), but it makes no difference.

any ideas anyone?