Check your 'php error log' if it is timing out it should report as such in a quite obvious fashion.
if the time required to run the install of the plugin is longer than
max_execution_time = 30
Then increase it to 60 and the 90 etc. Dont forget to put it back to 30 when the install completes or no more than 60. This is supposed to stop scripts with bugs from running for ever before they get kicked out.
PS A memory limit of 2048 meg is ridiculously high.I would suggest bringing that down to no more than 256 unless you are absolutely positive something needs more than that.