Error saving project

[Herbgarden]

Hi,

I have two projects which have suddenly got the same problem, when I go to
update them from project server and then need to save them before closing I
get this error: Cannot insert duplicate keyrow in MSP_Assignments with
unique index I_MSP_Assignments.

One project is actually our admin project and there definately are not any
duplicate rows in it. Its not even very big?

Any ideas?

Thanks