MonoDevelop fails to import mojoportal.sln because that file refers to "businessmojoPortal.Business.csproj" instead of "BusinessmojoPortal.Business.csproj" (not capital B). I'm not sure why VS.NET doesn't choke on it for the same reason. Presumably there is some sort Windows case-insensitivity quirk that allows it to work. Anyway, the following patch fixes the problem:
Index: mojoportal.sln
===================================================================
--- mojoportal.sln (revision 77)
+++ mojoportal.sln (working copy)
@@ -3,7 +3,7 @@
ProjectSection(ProjectDependencies) = postProject
EndProjectSection
EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "mojoPortal.Business", "businessmojoPortal.Business.csproj", "{8582D51E-126B-4D64-B080-07AD8245B38F}"
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "mojoPortal.Business", "BusinessmojoPortal.Business.csproj", "{8582D51E-126B-4D64-B080-07AD8245B38F}"
ProjectSection(ProjectDependencies) = postProject
EndProjectSection
EndProject