"Dynamic MMap has no space. Please increase the resolution of APT: Cache-Limit ..."

"Dynamic MMap has no space. Please increase the resolution of APT: Cache-Limit... ". when updating the software in javastun, the following error occurs: Java code jiyj @ ubuntu :~ $ Sudo apt-get install firefox [sudo] password for jiyj: Sorry, try again. [sudo] password for jiyj: www.2cto.com is reading the package list... An error occurred! E: Dynamic MMap has no space. Increase the size of APT: Cache-Limit. Current Value: 25165824. (Man 5 apt. conf) E: Error Handling python-webhelpers (NewFileDesc2) E: Problem with MergeList/var/lib/apt/lists/mirror.lzu.edu.cn _ ubuntu_dists_natty_universe_binary-amd64_Packages W: Unable to munmap E: unable to parse or open the package list or status file. Solution: Create a new file:/etc/apt. conf in the system and enter APT: Cache-Limit 99999999. Save the file. Run the following command on www.2cto.com: sudo gedit/etc/apt. conf: Enter APT: Cache-Limit 99999999 in the pop-up editor. Save the command.