The problem is caused by the doctype tag:
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
It is mssing the link to the DTD to use, so IE is going into Quirks mode. In Quirks mode, IE uses the 5.5 rendering engine.
change the doctype to:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
So that it will use the correct DTD.