diff --git a/modules/TDESetupPaths.cmake b/modules/TDESetupPaths.cmake
index 465df7f..97b565d 100644
--- a/modules/TDESetupPaths.cmake
+++ b/modules/TDESetupPaths.cmake
@@ -15,10 +15,14 @@
 
 macro( _tde_internal_setup_path _path _default _comment )
   if( DEFINED ${_path} )
-    set( ${_path} "${${_path}}" CACHE PATH "${_comment}" )
-  else( DEFINED ${_path} )
+    if( IS_ABSOLUTE ${${_path}} )
+      set( ${_path} "${${_path}}" CACHE PATH "${_comment}" FORCE )
+    else( )
+      set( ${_path} "${CMAKE_INSTALL_PREFIX}/${${_path}}" CACHE PATH "${_comment}" FORCE )
+    endif( )
+  else( )
     set( ${_path} "${_default}" )
-  endif( DEFINED ${_path} )
+  endif( )
 endmacro( _tde_internal_setup_path )