I don't think this is a bug, maybe a compilation issue - anyone else seen this before?

2010-06-24 10:58:02,080 ERROR mojoPortal.Web.Global - 129.82.251.10-en-US - /MemberList.aspx
System.Web.HttpParseException: Only Content controls are allowed directly in a content page that contains Content controls. ---> System.Web.HttpException: Only Content controls are allowed directly in a content page that contains Content controls.
   at System.Web.UI.FileLevelPageControlBuilder.AppendLiteralString(String text)
   at System.Web.UI.TemplateParser.ProcessLiteral()
   --- End of inner exception stack trace ---
   at System.Web.UI.TemplateParser.ProcessException(Exception ex)
   at System.Web.UI.TemplateParser.ProcessLiteral()
   at System.Web.UI.TemplateParser.ParseStringInternal(String text, Encoding fileEncoding)
   at System.Web.UI.TemplateParser.ParseString(String text, VirtualPath virtualPath, Encoding fileEncoding)

MemberList doesn't run at all on one of our installations and gives that error.  MemberList works fine on other installations running the same version on the same hardware (2.3.4.4).  Ideas?