Download accelerator is one of the cases where I disagree with PCAs recommendation, why ? Because it's Adware not freeware and funds itself with the targeted ad bar on the screen, this part of it is what Spybot is picking up.
Is it a threat ? probably not the information is supposedly put to 'respectable' use, but as it's spy ware it totally negates the point of putting Spybot on the PC, I wouldn't touch it with the proverbial barge pole. My preferences are click here Leechget or click here Download Express, both true freeware devoid of intrusive extras.
As to removing it I would first open the program and look at the settings, deactivating any update or monitoring options, then follow these instructions from the DA FAQ page click here
" To uninstall Download Accelerator Plus, either use the Uninstall utility under DAP's program group in the Start menu, or the Windows Control Panel "Add/Remove Programs" utility.
The change will take effect after you restart your browser. NOTE: Please make sure to exit Download Accelerator Plus before starting the uninstall operation."
If not try "My Uninstaller" click here