ESXi 5.0 Cannot Join vCenter, vpxa rogue folder cannot be removed

Hello,

we have an ESXi 5.0 that cannot be joined to vCenter 5.1

It fails with timed out waiting for vpxa to start.

the problem seems coming from:

/opt/vmware/vpxa/vpx # ls -lah

drwxrwxrwx    1 root     root          512 Mar  8 12:40 .

-r-xr-xr-x    1 root     root        29.7k Aug 19  2011 .#vpxResultFilter.xml

drwxrwxrwx    1 root     root          512 May 10  2012 ..

/opt/vmware/vpxa/vpx # rm -rf .\#vpxResultFilter.xml

rm: cannot remove '.#vpxResultFilter.xml': Operation not permitted

this file cannot be deleted.

The host has failed to join vCenter previously and the vpxa could not be uninstalled nor installed.

please you help

thank