Various minor fixes:

- better exceptions for faulty temporary directories
- better exception if client can not connect to JobManager

pom.xml

@@ -266,7 +266,6 @@
 		</profile>
 	</profiles>
 
-
 	<dependencyManagement>
 		<!-- this section defines the module versions that are used if nothing else is specified. -->
 		<dependencies>	
@@ -291,7 +290,6 @@
 
 	<reporting>
 		<plugins>
-
 			<!-- execution of Unit Tests -->
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
@@ -440,8 +438,8 @@
 						<configuration>
 							<rules>
 								<requireMavenVersion>
-									<version>(,2.1.0),(2.1.0,2.2.0),(2.2.0,)</version>
-									<message>Maven 2.1.0 and 2.2.0 produce incorrect GPG signatures and checksums respectively.</message>
+									<!-- enforce at least mvn version 3.0.3 -->
+									<version>[3.0.3,)</version>
 								</requireMavenVersion>
 							</rules>
 						</configuration>

stratosphere-compiler/src/main/java/eu/stratosphere/compiler/PactCompiler.java

@@ -1549,7 +1549,9 @@ public class PactCompiler {
 			throw new CompilerException(e.getMessage());
 		}
 		catch (Throwable t) {
-			throw new CompilerException("Error while connecting to the job manager: " + t.getMessage(), t);
+			throw new CompilerException("Cannot connect to the JobManager to determine the available TaskManagers. "
+					+ "Check if the JobManager is running (using the web interface or log files). Reason: " + 
+				t.getMessage(), t);
 		}
 
 		// determine which type to run on

stratosphere-runtime/src/main/java/eu/stratosphere/nephele/taskmanager/TaskManager.java

@@ -934,15 +934,15 @@ public class TaskManager implements TaskOperationProtocol {
 			final File f = new File(dir);
 
 			if (!f.exists()) {
-				throw new Exception("Temporary file directory #" + (i + 1) + " does not exist.");
+				throw new Exception("Temporary file directory '" + f.getAbsolutePath() + "' does not exist.");
 			}
 
 			if (!f.isDirectory()) {
-				throw new Exception("Temporary file directory #" + (i + 1) + " is not a directory.");
+				throw new Exception("Temporary file directory '" + f.getAbsolutePath() + "' is not a directory.");
 			}
 
 			if (!f.canWrite()) {
-				throw new Exception("Temporary file directory #" + (i + 1) + " is not writable.");
+				throw new Exception("Temporary file directory '" + f.getAbsolutePath() + "' is not writable.");
 			}
 		}
 	}