Erro ao gerar o .jar com jdk 1.5

Galera to usando o Net Beans e estou construindo meu projeti(gerando o jar) so que quando estou com a jdk 1.6 instalada na maquina rola perfitamente quando desinstalo a jdk 1.6 e instalo a 1.5 ele da esse erro

[code]init:
deps-jar:
Compiling 65 source files to V:\Aplicacao\build\classes
javac: invalid target release: 1.6
Usage: javac
where possible options include:
-g Generate all debugging info
-g:none Generate no debugging info
-g:{lines,vars,source} Generate only some debugging info
-nowarn Generate no warnings
-verbose Output messages about what the compiler is doing
-deprecation Output source locations where deprecated APIs are used
-classpath Specify where to find user class files
-cp Specify where to find user class files
-sourcepath Specify where to find input source files
-bootclasspath Override location of bootstrap class files
-extdirs Override location of installed extensions
-endorseddirs Override location of endorsed standards path
-d Specify where to place generated class files
-encoding Specify character encoding used by source files
-source Provide source compatibility with specified release
-target Generate class files for specific VM version
-version Version information
-help Print a synopsis of standard options
-X Print a synopsis of nonstandard options
-J Pass directly to the runtime system

FALHA NA EXECUÇÃO (tempo total: 2 segundos)
[/code]

ObS: preciso criar o jar usando a 1.5 alguem sabe o que faco?

valeu

?