Index: action_controller/caching.rb
===================================================================
--- action_controller/caching.rb        (revision 5487)
+++ action_controller/caching.rb        (working copy)
@@ -330,7 +330,7 @@
       def cache_erb_fragment(block, name = {}, options = nil)
         unless perform_caching then block.call; return end

-        buffer = eval("_erbout", block.binding)
+        buffer = eval(ActionView::Base.erb_variable, block.binding)

         if cache = read_fragment(name, options)
           buffer.concat(cache)
Index: action_view/helpers/text_helper.rb
===================================================================
--- action_view/helpers/text_helper.rb  (revision 5487)
+++ action_view/helpers/text_helper.rb  (working copy)
@@ -23,7 +23,7 @@
       # is equivalent to using:
       #   <%= "hello" %>
       def concat(string, binding)
-        eval("_erbout", binding).concat(string)
+        eval(ActionView::Base.erb_variable, binding).concat(string)
       end

       # If +text+ is longer than +length+, +text+ will be truncated to the length of
Index: action_view/helpers/capture_helper.rb
===================================================================
--- action_view/helpers/capture_helper.rb       (revision 5487)
+++ action_view/helpers/capture_helper.rb       (working copy)
@@ -56,15 +56,15 @@
       def capture(*args, &block)
         # execute the block
         begin
-          buffer = eval("_erbout", block.binding)
+          buffer = eval(ActionView::Base.erb_variable, block.binding)
         rescue
           buffer = nil
         end

         if buffer.nil?
-          capture_block(*args, &block)
+          capture_block(*args, &block).to_s
         else
-          capture_erb_with_buffer(buffer, *args, &block)
+          capture_erb_with_buffer(buffer, *args, &block).to_s
         end
       end

@@ -99,7 +99,7 @@
         end

         def capture_erb(*args, &block)
-          buffer = eval("_erbout", block.binding)
+          buffer = eval(ActionView::Base.erb_variable, block.binding)
           capture_erb_with_buffer(buffer, *args, &block)
         end

Index: action_view/base.rb
===================================================================
--- action_view/base.rb (revision 5487)
+++ action_view/base.rb (working copy)
@@ -183,6 +183,9 @@
     # that alert()s the caught exception (and then re-raises it).
     @@debug_rjs = false
     cattr_accessor :debug_rjs
+
+    @@erb_variable = '_erbout'
+    cattr_accessor :erb_variable

     @@template_handlers = HashWithIndifferentAccess.new