GraphExplorer widget compile problem

HI All, 

I want to use GraphExplorer for my application and I am getting this error durin compile. 

Please tell me how to fix it. below is the dependencies in my pom 
-------------------------------------------------------------------------------------------------------------
<dependency>
            <groupId>org.vaadin.addons</groupId>
            <artifactId>graph-explorer</artifactId>
            <version>0.7.2</version>
        </dependency>

<vaadin.version>7.7.3</vaadin.version>

---------------------------------------------------------------------------------------------------------------

[INFO] --- vaadin-maven-plugin:7.7.3:compile (default) @
[INFO] auto discovered modules [AppWidgetset]
[INFO] Using com.vaadin:vaadin-client version 7.7.3
[INFO] Using com.vaadin:vaadin-client-compiler version 7.7.3
[INFO] Compiling module AppWidgetset
[INFO] [ERROR] Unexpected internal compiler error
[INFO] java.lang.NoSuchFieldError: warningThreshold
[INFO]     at com.google.gwt.dev.javac.JdtCompiler$1.<init>(JdtCompiler.java:605)
[INFO]     at com.google.gwt.dev.javac.JdtCompiler.getStandardCompilerOptions(JdtCompiler.java:603)
[INFO]     at com.google.gwt.dev.javac.JdtCompiler.getCompilerOptions(JdtCompiler.java:633)
[INFO]     at com.google.gwt.dev.javac.JdtCompiler.doCompile(JdtCompiler.java:983)

thanks
Chahat

After a bit of investigtion, I found that there was a dependency conflict with

<dependency>
            <groupId>tomcat</groupId>
            <artifactId>jasper-compiler-jdt</artifactId>
            <version>5.5.23</version>
        </dependency>

Is it not possible to use both the dependencies?

thanks
Chahat