sqlbench alter table test fails as of build 1392

The query that fails is:

create bench i1 int not null i2 int not null i3 int not null i4 int not null i5 int not null i6 int not null i7 int not null i8 int not null,
insert into bench values ( 0,0,0,0,0,0,0,0)
insert into bench values ( 1,1,1,1,1,1,1,1)
insert into bench values ( 2,2,2,2,2,2,2,2)
insert into bench values ( 3,3,3,3,3,3,3,3)
insert into bench values ( 4,4,4,4,4,4,4,4)
insert into bench values ( 5,5,5,5,5,5,5,5)
insert into bench values ( 6,6,6,6,6,6,6,6)
insert into bench values ( 7,7,7,7,7,7,7,7)
insert into bench values ( 8,8,8,8,8,8,8,8)
insert into bench values ( 9,9,9,9,9,9,9,9)
..........
insert into bench values ( 995,995,995,995,995,995,995,995)
insert into bench values ( 996,996,996,996,996,996,996,996)
insert into bench values ( 997,997,997,997,997,997,997,997)
insert into bench values ( 998,998,998,998,998,998,998,998)
insert into bench values ( 999,999,999,999,999,999,999,999)
Time for insert (1000) 1 wallclock secs ( 0.04 usr 0.05 sys + 0.00 cusr 0.00 csys = 0.09 CPU)

ALTER TABLE bench ADD i9 integer,ADD i10 integer,ADD i11 integer,ADD i12 integer,ADD i13 integer,ADD i14 integer,ADD i15 integer,ADD i16 integer,ADD i17 integer,ADD i18 integer

Error executing 'ALTER TABLE bench ADD i9 integer,ADD i10 integer,ADD i11 integer,ADD i12 integer,ADD i13 integer,ADD i14 integer,ADD i15 integer,ADD i16 integer,ADD i17 integer,ADD i18 integer':
Error on rename of './test/bench.dfe' to '/tmp/#sql863090.dfe' (errno: 18)