Partition does not exist

I am running Informix 1.10 Turbo on a mini-system and I have some problems with the database. In the last two months, I have lost 3 tables and the error message says: 240: Could not open database file (FILENAME). 135: C-ISAM error: Partition does not exist.I cannot do anything with that table (select, update, unload etc). The only thing I can do is to rename the table and create a new table with that name. However, some of the data are gone because I store the data in raw disk. Question 1: Does anyone out there have problems similar to this? Question 2: We are going to install Informix 4.10 Online and according to the people from Informix, that will solve our problems. Is it true? Question 3: I do not like the idea of storing the data in raw disk because the data are not readable when something happens. Which method is better, storing in raw disk or cooked disk? Thanks in advance. Tony Chow