What is it?
Adobe Acrobat IE plugin - acroiehelper.ocx
What does it do?
If you'd like to open your PDF documents directly in IE you will want to keep this file. This is the browser plugin.
You'll want to keep an eye on this google search for any known viruses. The normal location of this file is C:Program FilesAdobeAcrobat 6.0ReaderActiveXAcroIEHelper.ocx