* KeepInFrame has a bug in ReportLab 2.0 not allowing maxHeight to be

  None, even though the wrap() method does the right thing and can handle 
  None and 0, both values disallowed.

* Make sure that we strip the <?xml ?> line only when dealing with a 
  unicode string.

src/z3c/rml/flowable.py

@@ -718,7 +718,7 @@ class IKeepInFrame(interfaces.IRMLDirectiveSignature):
 
 class KeepInFrame(Flowable):
     signature = IKeepInFrame
-    klass = reportlab.platypus.flowables.KeepInFrame
+    klass = platypus.KeepInFrame
     attrMapping = {'onOverflow': 'mode', 'id': 'name'}
 
     def process(self):

src/z3c/rml/platypus.py

@@ -21,6 +21,24 @@
 
 from z3c.rml import interfaces
 
+# Fix problem with reportlab 2.0
+class KeepInFrame(reportlab.platypus.flowables.KeepInFrame):
+
+    def __init__(self, maxWidth, maxHeight, content=[], mergeSpace=1,
+                 mode='shrink', name=''):
+        self.name = name
+        self.maxWidth = maxWidth
+        self.maxHeight = maxHeight
+        self.mode = mode
+        assert mode in ('error','overflow','shrink','truncate'), \
+               '%s invalid mode value %s' % (self.identity(),mode)
+        # This is an unnecessary check, since wrap() handles None just fine!
+        #assert maxHeight>=0,  \
+        #       '%s invalid maxHeight value %s' % (self.identity(),maxHeight)
+        if mergeSpace is None: mergeSpace = overlapAttachedSpace
+        self.mergespace = mergeSpace
+        self._content = content
+
 
 class BaseFlowable(reportlab.platypus.flowables.Flowable):
     def __init__(self, *args, **kw):

src/z3c/rml/rml2pdf.py

@@ -27,7 +27,7 @@
 
 
 def parseString(xml, removeEncodingLine=True):
-    if removeEncodingLine:
+    if isinstance(xml, unicode) and removeEncodingLine:
         # RML is a unicode string, but oftentimes documents declare their
         # encoding using <?xml ...>. Unfortuantely, I cannot tell lxml to
         # ignore that directive. Thus we remove it.