diff --git a/src/main/org/apache/ant/compress/taskdefs/ArchiveBase.java b/src/main/org/apache/ant/compress/taskdefs/ArchiveBase.java
index 230de45..309ff8f 100644
--- a/src/main/org/apache/ant/compress/taskdefs/ArchiveBase.java
+++ b/src/main/org/apache/ant/compress/taskdefs/ArchiveBase.java
@@ -329,7 +329,7 @@
                                      + " instance");
         }
         if (fileSetBuilder == null) {
-            throw new BuildException("subclass didn't provide an fileSetBuilder"
+            throw new BuildException("subclass didn't provide a fileSetBuilder"
                                      + " instance");
         }
         if (getDest() == null) {