[Lazarus] Divide by zero in my main form

[Richard Mace]

Hi,
I am getting a random weird error, that is not making any sense to me.
I have a main form that has a splitter and notebook and other bits and
pieces on it, and all is ok whilst working on the project, then, a few
times a week, when I load Lazarus from scratch and it loads my project, I
get a "divide by zero" error on the main form, even though, when I was last
compiling it, it was working fine.
When I then click on the tab with the ide, I get a "list index (-1) out of
bounds".
I am using Windows 8 and Lazarus 1.0.12 with the standard FPC that comes
with it.
I've attached the current problematic main.lfm form, and if anyone could
spare a few minutes to look at it, that would be great.
I really don't understand it as I can restore an old main.lfm file from a
backup and all is well for a few more days, and then, bang, the same thing
happens.

Thanks in advance for any help.
Richard
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