Help with this error message

[elthznd901]

I have searched the net.. and maybe I am just not getting lucky but although I find many people with a similar issue.. none seem to directly relate.  Have a hosted server running a mix of mods, although much less from when I used to run my hexxit server and I didnt have this issue.  I am getting some lag(mostly noticable with block breaking) and the Cant Keep up did the system time change message.  Forgive my noobness, but is there any way I can tell where the issue is coming from? Is it something server side I can have them set?  I see the message every few seconds or so with an occasional 5 min break.  Most of the time server perfomance is just ok, but when its not you get quite a bit of the breaking of the blocks re-appearing.

 

Thanks!