First of all if you don't know to use the program read the manual, then if you still have some problems come here and ask. But very important, before starting to work try to work tidy, set your project where to save your work and temporary files (take care never delete temporary files until your project is finished). Don't forget to have enough space and you will never have problems like those described above.

As a suggestion if you don't want to update your program to release 11 because is too expansive for you, I suggest you to update to v9.4 which is the best version from v9 series.

good luck!