FieldPolynomialRingOps.StandardAssociate still has the same bug as
3r4p2 when called with the 0 polynomial:

gap> x:=X(Rationals);
X(Rationals)
gap> StandardAssociate(0*x);
Error, List Element: <position> must be a positive integer at
return f * f.coefficients[Length( f.coefficients )] ^ (-1 * 1) ... in
R.operations.StandardAssociate( R, r ) called from
StandardAssociate( 0 * x ) called from
main loop
brk> `

A fix for 3r4p2 was available, but has been left out:
--- polyfld.g  Mon Jul 31 13:54:20 1995
+++ polyfld.g.orig   Mon Jul 31 13:53:09 1995
@@ -58,9 +58,6 @@
 #F  FieldPolynomialRingOps.StandardAssociate( <R>, <f> )  . . . .  normed pol
 ##
 FieldPolynomialRingOps.StandardAssociate := function( R, f )
-    if Length(f.coefficients)=0 then
-      return Zero(R);
-    fi;
     return f * f.coefficients[ Length( f.coefficients ) ]^-1;
 end;

Helmut Geyer