can't import variance covariance matrix message in robust de

[Belinda Cannell]

I am trying to use a robust design with nestbox data from 1993-current. The nestboxes are used by Little Penguins, and have been checked regulalry, but with no consistent time interval. I have chosen the Sept-Dec period to incorporate into this design. I have 164 encounters, with 14 primary sessions and variable numbers of secondary sessions (from 6 - 17). I also have no data in 2004 and 2005 when no checks were made. I have set the time intervals manually, typing in a 3 (not a 1) to indicate the gap in data collection from 2003 to 2006. When I try to run various models (eg S(.)gamma"(.)gamma'(.) pprimary(t)=cprimary(t)psecondary(.)=csecondary(.); S(.) gamma"(.)gamma'(.) pprimary(s)=cprimary(s)psecondary(.)=csecondary(.) and more) I keep getting the message that the variance-covariance matrix could not be imported. Any ideas what I am doing wrong?