diff --git a/src/build/toolset.py b/src/build/toolset.py
index 3665ab872..e969123d4 100644
--- a/src/build/toolset.py
+++ b/src/build/toolset.py
@@ -362,7 +362,7 @@ def __add_flag (rule_or_module, variable_name, condition, values):
     assert m
     module = m.group(1)
 
-    __module_flags.setdefault(m, []).append(f)
+    __module_flags.setdefault(module, []).append(f)
     __flags.setdefault(rule_or_module, []).append(f)
 
 __requirements = []
diff --git a/src/tools/common.py b/src/tools/common.py
index b1ee26f0c..7a9348bf2 100644
--- a/src/tools/common.py
+++ b/src/tools/common.py
@@ -173,6 +173,7 @@ def check_init_parameters(toolset, requirement, *args):
 
         The return value from this rule is a condition to be used for flags settings.
     """
+    from b2.build import toolset as b2_toolset
     # The type checking here is my best guess about
     # what the types should be.
     assert(isinstance(toolset, str))
@@ -233,6 +234,11 @@ def check_init_parameters(toolset, requirement, *args):
         
         sig = sig + value + '-'
 
+    # if a requirement is specified, the signature should be unique
+    # with that requirement
+    if requirement:
+        sig += '-' + requirement
+
     if __all_signatures.has_key(sig):
         message = "duplicate initialization of '%s' with the following parameters: " % toolset
         
@@ -255,7 +261,7 @@ def check_init_parameters(toolset, requirement, *args):
     if requirement:
         r = ['<toolset>' + toolset, requirement]
         r = ','.join(r)
-        toolset.add_requirements([r + ':' + c for c in subcondition])
+        b2_toolset.add_requirements([r + ':' + c for c in subcondition])
 
     # We add the requirements, if any, to the condition to scope the toolset
     # variables and options to this specific version.
diff --git a/src/tools/midl.py b/src/tools/midl.py
index 43bcdf6fe..86c1f34b6 100644
--- a/src/tools/midl.py
+++ b/src/tools/midl.py
@@ -22,7 +22,7 @@ type.register('IDL', ['idl'])
 # to resources of an application (.rc). In order to be found by a resource 
 # compiler its target type should be derived from 'H' - otherwise
 # the property '<implicit-dependency>' will be ignored.
-type.register('MSTYPELIB', 'tlb', 'H')
+type.register('MSTYPELIB', ['tlb'], 'H')
 
 # Register scanner for MIDL files
 class MidlScanner(scanner.Scanner):
diff --git a/src/tools/msvc.py b/src/tools/msvc.py
index 1f9cc2ccb..7daadffd9 100644
--- a/src/tools/msvc.py
+++ b/src/tools/msvc.py
@@ -115,7 +115,10 @@ def init(version = None, command = None, options = None):
     command = to_seq(command)
     
     if command:
-        options.append("<command>"+command)
+        if isinstance(command, str):
+            options.append('<command>' + command)
+        else:
+            options.extend("<command>"+cmd for cmd in command)
     configure(version,options)
 
 def configure(version=None, options=None):
diff --git a/src/util/path.py b/src/util/path.py
index 011be7370..d602598c9 100644
--- a/src/util/path.py
+++ b/src/util/path.py
@@ -446,7 +446,11 @@ def programs_path ():
     for elem in raw:
         if elem:
             for p in elem.split(os.path.pathsep):
-                result.append(make(p))
+                # it's possible that the user's Path has
+                # double path separators, thus it is possible
+                # for p to be an empty string.
+                if p:
+                    result.append(make(p))
 
     return result