& Causing Validation Problems

I have some code on my application like the following:

<%

redirectUrl = "mypage.asp?type=100&id=something&view=10

'some more asp code

%>

<a href="<%=redirectUrl%>">Some Link</a>

the above code works fine but throws validation errors.

the errors are

# olumn 81: cannot generate system identifier for general entity "id".

An entity reference was found in the document, but there is no reference
by that name defined. Often this is caused by misspelling the reference
name, unencoded ampersands, or by leaving off the trailing semicolon
(;). The most common cause of this error is unencoded ampersands in URLs
as described by the WDG in "Ampersands in URLs". Code: