misc: Avoid using the CharacterArray>>% as it is not available in Pharo

Dispatcher.st

@@ -61,7 +61,7 @@ Object subclass: Dispatcher [
         to make sure we keep on processing items in order."
         [[
         block on: Error do: [:error |
-            error logException: 'dispatch failed on "%1".' % {block} area: #core.
+            error logException: ('dispatch failed on "', block printString, '".') area: #core.
         ]] ensure: [sem signal]] fork.
 
         sem wait.

Timer.st

@@ -155,7 +155,8 @@ bit difficult to do this race free.'>
             each := sem critical: [queue removeFirst].
             each isCanceled ifFalse: [
                 [each fire] on: Error do: [:e |
-                e logException: 'Execution of timer failed: %1' % {e tag} area: #timer.
+                e logException:
+                    ('Execution of timer failed: ', e messageText) area: #timer.
             ]].
         ]
     ]