I think it would help if you tell which IRCAM externals you use in your patch...
Or maybe you've got this error when launching Max ?
Which version of Max ?
Some IRCAM externals have their own website like FTM you may be more succeful on these.
If the operativ system of your new computer is different than the other(where the externals worked)
is very probable that the IRCAM externals won't work (that happened to me once), The version has to be exacly the same, 'cause a littel diference can bring problems.
so, better idea to write to IRCAM technical support.