Fix typo: AVAIABLE->AVAILABLE.

--- a/src/wrapevolve.F
+++ b/src/wrapevolve.F
@@ -315,7 +315,7 @@
       if(index(setpath,'NNPDF').gt.0) then
           if(nset.gt.1) then
               if((index(setpath,'1000.').gt.0.and.nnpdf.gt.0).or.(index(setpath,'100.').gt.0.and.nnpdf1000.gt.0)) then
-                  print *,'LHAPDF ERROR: MULTISET-INITIALIZATION with NNPDF 1000 sets IS NOT AVAIABLE (AT THE MOMENT)!'
+                  print *,'LHAPDF ERROR: MULTISET-INITIALIZATION with NNPDF 1000 sets IS NOT AVAILABLE (AT THE MOMENT)!'
                   STOP
               endif
           endif