Create download and choose output folder to the one where uncompleted file is located. Uncheck "generate file name automatically" option and set file name to identical to name of uncompleted file.
When FDM ask you what to do, click on Resume button.

This feature will appeare in one of the next versions.

I've just tried to download - OK.

This site uses non standart port. Have you any firewalls installed on your computer?

Thank you. Bug was fixed.

SHIFT+DEL

You can change default path for downloads in Group properties.

Fixed. Please wait for the next version.

SHIFT+DEL key combination deletes file from disk too, EVEN if download was completed.

DEL key removes (or not, depens on settings) only uncompleted files.

Please tell me how you setup Traffic usage modes.

Heavy Mode:

Max number of conns: ???
Max number of conns per server: ???
Max number of running downloads: ???

And for Medium Mode and Light Mode.

Please give URL example.

Options->Default download settings->Miscellaneous->Reserve disk space for downloading file.

Dear user,

We have added support for > 4Gb files.

Please download and test:

http://www.freedownloadmanager.org/fdm_hs.exe

Please test how it works with HTTP and FTP.

Yes. These 2 problems was fixed.

Could you please describe a sequence of actions resulting in a bug in detail.