URGENT - ESX 3.5 hanging

Hi, I've got an ESX 3.5 host that keeps 'hanging' i.e. the VI client will disconnect, my monitoring software (currently using Veeam Monitor) will disconect and the uptime for all the VMs running on the box will reset to 0.

Here's a snip from the log file:

Event 17297 : User root@127.0.0.1 logged in

Event 17298 : User root logged out

Event 17299 : User root@127.0.0.1 logged in

Event 17300 : User root logged out

Caught signal 11

Event 17301 : User root@127.0.0.1 logged in

Backtrace:

eip 0x22746ee 

eip 0x213e789 

eip 0x2274217 

eip 0x86be992 

eip 0x970f88 

eip 0xff9508 

eip 0x1000979 

eip 0x1002191 

eip 0x1000c64 

eip 0x1002191 

eip 0x10016c1 

eip 0x100226a 

eip 0x100062c 

eip 0x1002432 

eip 0x1013b79 

eip 0x822f292 

eip 0x82301f1 

eip 0x822fe67 

eip 0x823683a 

eip 0x2283db2 

eip 0x227e1c2 

eip 0x2282b8a 

eip 0x22797d7 

eip 0x96add8 

eip 0x3dbcfca 

Worker: Unhandled exception:

basic_string::_S_create

Exception while processing request: Broken pipe

Worker: Unhandled exception:

basic_string::_S_create

Worker: Unhandled exception:

basic_string::_S_create

Exception while processing request: Broken pipe

What can I do to fix this? Is it something I've done.

Let me know if you need any further info. There's a drink in it for anyone who can help me out

Richard