fatal two-task communication protocol error

[Lysen]

Hi group,

when running a cognos impromptu report on our oracle 8i database it returns the following error, when 4 elements from "elm1" are selected (elm1 being a prompt)
:

DMS-E-GENERAL, A general exception has occurred during operation 'asynchronous open'.
DMS-E-GENERAL, A general exception has occurred during operation 'fetch'.
ORA-03106: fatal two-task communication protocol error

if 1 of the 4 elm1 elements is chosen, the report runs fine, so I guess it's not a cognos problem... ?? does anyone know what this error means and/or how to solve it??

Thanks in advance...