diff --git a/src/java/com/threerings/presents/tools/GenReceiverTask.java b/src/java/com/threerings/presents/tools/GenReceiverTask.java
index c48c88f8f..b62b60ece 100644
--- a/src/java/com/threerings/presents/tools/GenReceiverTask.java
+++ b/src/java/com/threerings/presents/tools/GenReceiverTask.java
@@ -122,7 +122,7 @@ public class GenReceiverTask extends InvocationTask
             // determine the path to our sender file
             String mpath = source.getPath();
             mpath = StringUtil.replace(mpath, "Receiver", "Sender");
-            mpath = StringUtil.replace(mpath, "/client/", "/server/");
+            mpath = replacePath(mpath, "/client/", "/server/");
 
             writeFile(mpath, sw.toString());
 
diff --git a/src/java/com/threerings/presents/tools/GenServiceTask.java b/src/java/com/threerings/presents/tools/GenServiceTask.java
index b0056effa..ef0089362 100644
--- a/src/java/com/threerings/presents/tools/GenServiceTask.java
+++ b/src/java/com/threerings/presents/tools/GenServiceTask.java
@@ -186,7 +186,7 @@ public class GenServiceTask extends InvocationTask
             // determine the path to our marshaller file
             String mpath = source.getPath();
             mpath = StringUtil.replace(mpath, "Service", "Marshaller");
-            mpath = StringUtil.replace(mpath, "/client/", "/data/");
+            mpath = replacePath(mpath, "/client/", "/data/");
 
             writeFile(mpath, sw.toString());
 
@@ -229,7 +229,7 @@ public class GenServiceTask extends InvocationTask
             // determine the path to our marshaller file
             String mpath = source.getPath();
             mpath = StringUtil.replace(mpath, "Service", "Dispatcher");
-            mpath = StringUtil.replace(mpath, "/client/", "/server/");
+            mpath = replacePath(mpath, "/client/", "/server/");
 
             writeFile(mpath, sw.toString());
 
@@ -269,7 +269,7 @@ public class GenServiceTask extends InvocationTask
             // determine the path to our provider file
             String mpath = source.getPath();
             mpath = StringUtil.replace(mpath, "Service", "Provider");
-            mpath = StringUtil.replace(mpath, "/client/", "/server/");
+            mpath = replacePath(mpath, "/client/", "/server/");
 
             writeFile(mpath, sw.toString());
 
diff --git a/src/java/com/threerings/presents/tools/InvocationTask.java b/src/java/com/threerings/presents/tools/InvocationTask.java
index fccf6f66f..9c0a81138 100644
--- a/src/java/com/threerings/presents/tools/InvocationTask.java
+++ b/src/java/com/threerings/presents/tools/InvocationTask.java
@@ -315,6 +315,14 @@ public abstract class InvocationTask extends Task
         return (didx == -1) ? name : name.substring(0, didx);
     }
 
+    protected static String replacePath (
+        String source, String oldstr, String newstr)
+    {
+        return StringUtil.replace(source,
+                                  oldstr.replace('/', File.separatorChar),
+                                  newstr.replace('/', File.separatorChar));
+    }
+
     /** A list of filesets that contain tile images. */
     protected ArrayList _filesets = new ArrayList();