maven2 & eclipse

Hi experts,

   I have maven2 and eclipse and they worked fine for most projects. Now I just download some source code from web, I tried to complie it as following and got the folllowing errors ... what should I change exactly?

   I have some other projects which work fine using the current setting, and I don't want to destroy the current projects. So what should I do to fix the following problem? Thanks.
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C:\Project>mvn eclipse:eclipse

ERROR: JAVA_HOME is set to an invalid directory.
JAVA_HOME = C:\jdk1.5.0_06\bin\;C:\jre1.5.0_06;C:\jdk1.5.0_06;
Please set the JAVA_HOME variable in your environment to match the
location of your Java installation