This is the forum for Notes/Domino 6 and 7.
You are using 9.01. You should probably go here: http://www-10.lotus.com/ldd/ndseforum.nsf
But the people there won't tell you anything different from this: your problem is in your application. The cause cannot be determined without looking at the application code. You need to have your application developer look at the source code and maybe use the LotusScript debugger to figure it out. If you don't have an application developer, then you need to engage the services of a qualified consultant with a few years (or decades) of experience working with Lotus Notes and LotusScript. There are still a few of those around.