diff --git a/source/org/thdl/tib/text/TibTextUtils.java b/source/org/thdl/tib/text/TibTextUtils.java
index 4e2ef71..695b093 100644
--- a/source/org/thdl/tib/text/TibTextUtils.java
+++ b/source/org/thdl/tib/text/TibTextUtils.java
@@ -1649,7 +1649,9 @@ public class TibTextUtils implements THDLWylieConstants {
         if (!TibetanMachineWeb.isKnownHashKey(root)) {
             root = root.replace('+', '-');
             if (!TibetanMachineWeb.isKnownHashKey(root)) {
-                throw new Error("root is, now, " + root); // FIXME: make this an assertion
+                // If the glyph isn't even in TibetanMachine, then
+                // it's not able to take any prefix.
+                return false;
             }
         }
         String ru = TibetanMachineWeb.getUnicodeForWylieForGlyph(root);
diff --git a/source/org/thdl/tib/text/ttt/PackageTest.java b/source/org/thdl/tib/text/ttt/PackageTest.java
index 1e10d75..b0e2ca5 100644
--- a/source/org/thdl/tib/text/ttt/PackageTest.java
+++ b/source/org/thdl/tib/text/ttt/PackageTest.java
@@ -465,6 +465,9 @@ tstHelper("KA'", "[(K . A), (' . )]",
         tstHelper("DAM'O", null, null, null, "{DA}{M}{'O}", 2);
         tstHelper("D-M'O", null, null, null, "{D}{M'O}", -1);
 
+        tstHelper("GTZAN", "{G}{TZA}{N}", null, null, "{G}{TZA}{N}", -1);
+        tstHelper("GTZHAN", "{G}{TZ}{HA}{N}", null, null, "{G+TZ+HA}{N}", -1);
+
         tstHelper("SHR'I", "{SH}{R'I}",
                   null,
                   null,