diff --git a/pregelix/pregelix-core/pom.xml b/pregelix/pregelix-core/pom.xml
index 576758b..7b247a8 100644
--- a/pregelix/pregelix-core/pom.xml
+++ b/pregelix/pregelix-core/pom.xml
@@ -18,8 +18,9 @@
 	<build>
 		<plugins>
 			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-jar-plugin</artifactId>
-				<version>2.4</version>
+				<version>2.3.2</version>
 				<executions>
 					<execution>
 						<id>balancer</id>
@@ -72,7 +73,7 @@
 			<plugin>
 				<groupId>org.codehaus.mojo</groupId>
 				<artifactId>appassembler-maven-plugin</artifactId>
-				<version>1.3</version>
+                <version>1.3</version>
 				<executions>
 					<execution>
 						<configuration>
@@ -164,7 +165,7 @@
 			</plugin>
 			<plugin>
 				<artifactId>maven-clean-plugin</artifactId>
-				<version>2.5</version>
+                <version>2.4.1</version>
 				<configuration>
 					<filesets>
 						<fileset>