Error in querying view

Hi

    I don't know whether this has been fixed in 6.4 -- I still cannot get
6.4 to compile and run on Alpha -- but I have the following error when
querying a view in 6.3.2:

I have a table with jobs/tasks (one job can consist of several tasks)
that need to be executed, and have created a relatively complicated view
(tasks_todo) on this table, which gives me all jobs that are finished.
When I then try to create the following very simple view, I get an
error:

cb=> create view jobs_done as select j.job from jobs j where not j.job
in (select job from tasks_todo);
CREATE
cb=> select * from jobs_done;
ERROR:  ExecEvalExpr: unknown expression type 108
cb=> select * from tasks_todo;
job|task|priority|joblink|state
---+----+--------+-------+-----
 58|  58|       3|      0|    4
 67|  67|       3|      0|    4
 44|  44|       3|      0|    4
 61|  61|       3|      0|    4
 70|  70|       5|      0|    4
 88|  96|       3|     80|    2
 89|  97|       3|     76|    0
 90|  98|       3|     77|    0
 91|  99|       3|     78|    0
 92| 100|       3|     79|    0
 95| 103|       3|     82|    0
 93| 101|       3|     80|    0
 96| 104|       3|     80|    2
100| 108|       3|     81|    0
112| 120|       3|    101|    0
113| 121|       3|     73|    0
111| 119|       3|     74|    0
(17 rows)

cb=> select j.job from jobs j where not j.job in (select job from
tasks_todo);
job
---
 55
 57
 59
 60
 42
 56
 74
 75
 77
 78
 79
 80
 81
 73
 86
 85
 87
 76
101
 82
(20 rows)


So, is there a problem with using NOT..IN.. in a view?

Any help appreciated,

Adriaan