ERROR- sitemap.xml "Plugin Missing."

I have 1.0.3 installed and I get the sitemap at the main site but I do not get it at the sub-sites in my network. works fine gets error

Plugin Missing. gets error

The XML page cannot be displayed

Cannot view XML input using XSL style sheet. Please correct the error and then click the Refresh button, or try again later.

Access is denied.

We had previously installed the Sitemaps plugin from WPMUDEV but uninstalled it when we installed the newest SEO plugin. What did I do wrong?