thumbs.db

I have discovered that a "thumbs.db" file in my WebHelp project is causing some trouble on one of my company's web servers. I was not able to delete some folders on that server, and asked an intranet development person to delete them for me. She said that that web support said it apparently was because I had "thumbs.db" files that were "system files." She was able to delete them. Now, when I try to copy (via FTP) my RoboHelp project from my C: drive to the web server, it apparently is suddenly rejecting the "thumbs.db" file (although everything else looks like it copied OK, so I guess that means the "thumbs.db" problems will not reoccur, other than WS FTP-Pro making a nasty noise when it rejects the files?). I didn't see a "thumbs.db" file anywhere on my C: drive until I deselected "Hide protected operating system files (recommended)," and now I see it. (I am using Windows XP Professional op system.)

Another thing that was wierd was that I have renamed the folder that contains "thumbs.db" on my C: drive to AEHelp, but Search finds the "thumbs.db" file only under the old folder name (NAOHelp).

What is this file and can I delete it from my C:drive?