If anybody cares to undergo an archaelogical study in the sources of CMS
to find the cause of the problem, the following exec is 3.7 times slower
under 5.5. The long complex expression is basically equivalent to 'a=a',
but it shows that we can expect  very serious performance degradation on
complex expressions under CMS 5.5 /Eric
 
/* Reach for the top! */
 a = Copies('*',10000)
 Do 1000
    a = Left(Left(Left(Left(a,Length(a)),Length(a)),Length(a)),Length(a))
 End