Whats the call stack for the error and what client you using ? 
Is the error client side or server side? Is there an error in the server side log?

My guess is there is something wrong in the way your are creating the UUID for the colum and super column names, rather than for the key. You can use UUID for the key as a string (or byte array in 0.7) so a badly formatted value will not matter. 


On 19 Oct, 2010,at 05:25 AM, "cbertu81@libero.it" <cbertu81@libero.it> wrote:

I am getting crazy using TimeUUID in cassandra via Java. I've read the FAQ but
it didn't help.
Can I use a TimeUUID as ROW identifier? (if converted to string)

I have a CF like this and SCF like these:

<ColumnFamily Name="Opecs" CompareWith="TimeUUIDType"/>
phone: 123
address: street xyz

<ColumnFamily Name="UserOpecs" ColumnType="Super" CompareWith="TimeUUIDType"
CompareSubcolumnsWith="BytesType" />
String USERID (ROW) {
TIMEUUID OPECID (SuperColumnName) {
collection of columns;

In one situation the TimeUUID is a ROW identifier while in another is the
SuperColumn name. I get many "UUID must be a 16 byte" when I try to read a data
that did not give any exception during his save.

at a Time T0 this one works: mutator.writeColumns(UuidHelper.timeUuidFromBytes
(OpecID).toString(), opecfamily, notNull); // (notnull contains a list of
columns also opecstatus)

Immediately after this one raise an exception: selector.getColumnFromRow
(UuidHelper.timeUuidFromBytes(OpecID).toString(), opecfamily, "opecstatus",

I hope that someone help me understanding it ..