diff --git a/doc/ant.xml b/doc/ant.xml
index 762e04c..b5fc7e5 100644
--- a/doc/ant.xml
+++ b/doc/ant.xml
@@ -13,7 +13,7 @@ like the following.
            <pathelement path="${src.java.dir}"/>
          </path>
        <javadoc sourcepathref="uml.source.path" packagenames="*" package="true">
-           <doclet name="org.umlgraph.doclet.UmlGraph" path="${basedir}/lib/UMLGraph.jar">
+           <doclet name="org.umlgraph.doclet.UmlGraph" path="${basedir}/lib/UmlGraph.jar">
                <param name="-d" value="${uml.dir}"/>
            </doclet>
        </javadoc>
diff --git a/doc/ver.xml b/doc/ver.xml
index 250c500..9aad6d6 100644
--- a/doc/ver.xml
+++ b/doc/ver.xml
@@ -6,7 +6,10 @@
 <dt>Version 5.2 Under development </dt><dd>
 <ul>
 <li> Corrected case of the tools.jar filename in the umlgraph shell script.
-(Noted by &#216;yvind Jergan).
+(Reported by &#216;yvind Jergan).
+</li>
+<li> Fixed exception when an unknown class dependency is specified.
+(Reported by Jan Schl&#252;ter).
 </li>
 </dd>
 
diff --git a/src/org/umlgraph/doclet/ClassGraph.java b/src/org/umlgraph/doclet/ClassGraph.java
index 2c08881..9b2a953 100644
--- a/src/org/umlgraph/doclet/ClassGraph.java
+++ b/src/org/umlgraph/doclet/ClassGraph.java
@@ -1043,7 +1043,8 @@ class ClassGraph {
 	
 	private String getPackageName(String className) {
 		if (this.rootClassdocs.get(className) == null) {
-			return className.substring(0, className.lastIndexOf('.'));
+			int idx = className.lastIndexOf('.');
+			return idx > 0 ? className.substring(0, idx) : "";
 		} else {
 			return this.rootClassdocs.get(className).containingPackage().name();
 		}
@@ -1051,7 +1052,8 @@ class ClassGraph {
 	
 	private String getUnqualifiedName(String className) {
 		if (this.rootClassdocs.get(className) == null) {
-			return className.substring(className.lastIndexOf('.') + 1);
+			int idx = className.lastIndexOf('.');
+			return idx > 0 ? className.substring(idx + 1) : className;
 		} else {
 			return this.rootClassdocs.get(className).name();
 		}