Hi lennart,
I follow your indication. And my charmm version is 42b2. Firstly, I modify the ../charmm/source/ltm/dimens_ltm.src (" NMCATM = 999999"). Then, I backed to the ../charmm file and performed command "./install.com gnu M". But the error still exit. Where was my performence wrong? Thanks a lot for your replying.