KeePass: Auto-Complete in IE8

I use KeePass Portable on different machines but am having a problem with using it on my IE8 browser at work.

Instead of pasting
user name
password

it pastes
ser name
password

It misses that first character of the user name every time.

Since my usernames often begin with the letter K I can type a K in the username field on the website and then Auto-Complete works fine. This never happens in Firefox or Chrome, only IE8. My work computer is an old Pentium 4 running Windows XP Pro SP3.