Easy way, download a file manager like Astro.

Or just open the browser and hit menu, downloads, long press on the file and hit clear from list and delete.

Sent from my Eris using Tapatalk

 

If you mount the Eris on your computer you can delete it from the SD card from your computer.

 

I did it by clicking 'My Files', then 'Downloads'. Just click the box(es), then the trash can. Job done!

 

Download Android file manager app open it and click download and then click on file you want to delete and hold until a window pops up select delete