NAV installing problem

Hi! I'm the one that try to install NAV in Debian. But I stucked at "aptitude install nav" command as Terminal told me "the following packages have unmet dependencies: nav :Depends: java5-runtume which is a virtual package. or sun-java5-jre which is a virtual package. Resolving dependencies"" the following action will resolve these dependencies: Keep the following packages at their currect version: nav [Not installed] python-pysnmp-common[Not installed] python-pysnmp2 [Not installed] python-pysnmp4 [Not installed] python-pysnmp4-mibs [Not installed] Score is -9965 Accept this solution? [Y/n/q/?]" What should i do next? Any help will be grateful My country is hard to find some experts to fix this problem T_T