Can't download purchases

Hi Guys,

Yesterday I made three purchases of modules in the marketplace.  2 were from one vendor and one from another.

I've had an email from one saying that he has manually added the module and certainly all three show me the "download" button rather than the price now.

BUT, when I hit "download" the box pops up "empty".  The downloads folder remains empty and I cannot access the modules.

Any thoughts on fixing this?  I thought it might be a cache thing, but it's the same on a different browser.

Thanks in advance

M