Sounds like the person that you're getting the files from isn't sending them, or their bandwidth is too full to send them, so the get command from your end isn't seeing the transfer in a reasonable amount of time, therefore generating a Time Out error.
You can adjust the timeout delay in mIRC Options - DCC - Options
Please note that under normal circumstances requests regarding filesharing (which is what it sounds like you're doing) are not answered in this forum.
