Try adding the following line(s) to your jserv.properties file (the comment header is 
probably already there, just add the non-commented wrapper.env.copy statement because I don't think one is there by default): 

    # An environment name with value passed to the JVM 
    # Syntax: wrapper.env=[name]=[value] 
    # Default: NONE on Unix Systems 
    #         SystemDrive and SystemRoot with appropriate values on Win32 systems 
    #wrapper.env=winbootdir=C:\WINDOWS 
    #wrapper.env=JAVA_HOME=C:\JDK1.2 
    wrapper.env=windir=C:\WINDOWS 

See Apache JServ problem #3642 in the bug list for details.