ASP Shopping cart help

[pse]

I have a shopping cart that was done by someone else a while ago and it has suddenly stopped working. It is in ASP not ASP.net Three different pages have the same type of code line in each. Here are the lines of code:

Page one:

<input name="Button" type="button" onClick="MM_goToURL('parent','shop-browse.asp');return document.MM_returnValue" value="Shop More">

Page two:

<input name="Button" type="button" onClick="MM_goToURL('parent','shop-browse.asp');return document.MM_returnValue" value="Shop More">

Page three:

<input name="Button" type="button" onClick="MM_goToURL('parent','https://www.pse.org/shop-checkout2.asp');return document.MM_returnValue" value="CONTINUE TO CHECKOUT >>">

These are the only pages within the shopping cart code that do not work. I can add things to the cart without any problems. Each page shows the same error. "Object expected" from a line on the page that does not exist. Any suggestions?

Thanks,
Tracy