Correct jQuery configuration in Magento installation

My Magento installation/websites have a few extensions which use JQuery. Most of the functionality is fine in Firefox,but a few issues have occurred in Chrome, Safari and I.E. Having looked at I.E I can see there is a js error as follows ---------------------------------------------------- Object Expected [login to view URL] Line:22 ---------------------------------------------------- Object doesn't support this property or method [login to view URL] Line: 134 Code: 0 Char: 2 URI:......... --------------------------------------------------- Line 22 is..... jQuery("[login to view URL]").hover(function(e){ Line 134 is.....jQuery(document).ready(function(){ screenshotPreview(); imgpreview is a function to popup a larger product image and is working OK in FF,Chrome and Safari, however I believe there is a conflict somewhere and need it resolving. If you think you can solve this fairly quickly please bid as this is a little beyond me. Thank you.