Make sure your Java's up to date, use the offline installer here
http://www.java.com/en/download/manual.jsp
A security or antispyware app might be seeing LW as a threat... are you using any antispy? Make sure that LW's on the list of exceptions/allowed apps. Or you could try disabling your antispy & see whether the same thing happens.
Has this always happened or is it a new problem?