JQuery Check the cause of the error in IE 7 and 8

Using jQuery 1.5.2 to get javascript error:

Error: '$.validator.methods[...]' is null or not an object

I tested it in IE7 and IE8 and got an error. Validation works fine in Firefox 4 and earlier.

When moving from the field address1 to address2. In fact, when you click from address 1 with the information in it on addres2 without information. In addition ... it is strange when a tab or click from the Zip field to the county field I do not get any error with information in or from the zip and / or county ... In addition, in the zip field there is an input masking check on which no county. I used jQuery 1.4.2 and saw this answer to a similar question ( JQuery Validator does not work in IE 7 or 8 ). I used jQuery 1.4.2 and upgraded to 1.5.2 with the same results.

Here is my verification code.

$('#frm_subefoLocation').validate({
  rules: {
    address1: { require:true,maxlength:100,minlength:2},
    address2: { require:false,maxlength:100},
    city: { require:true,maxlength:100,minlength:2},
    zip: { required:true,minlength:5,maxlength:10,number:true},
    county: { require:false,maxlength:100,minlength:0},
    mailAddress1: { require:true,maxlength:100,minlength:2},
    mailAddress2: { require:false,maxlength:100,minlength:0},
    mailCity: { require:true,maxlength:100,minlength:2},
    mailZip: { required:true,minlength:5,maxlength:10,number:true}
  }
});

Here is the hidden input code:

// set up mask for entry
$('#zip').mask('99999');

Any ideas?