Plugin Development. Plugin crashes

[Munawwar]

Been developing a Pidgin plugin (on and off for weeks). The plugin is to
show a popup window displaying the emails which the user has received.
Internally when a set of emails are recieved, I am allocating heap space and
appending the info into a list (glib singly-linked list).

The problem:
When an email is recieved, it shows the window as expected. However, when
the next mail is received, I intend the window to close, deallocate memory,
then repeat the procedure as it was done for the first mail (allocate memory
and show window). but it crashes at line number 130.
Source code: https://gist.github.com/76856c3fd3a334a77d3d
Crash report and debug messages: http://pastebin.com/eTBfSgxj
OS: Windows 7
Pidgin version: 2.10.0
MinGW, GCC compiler: 4.4.0

Seems very odd, since line number 130 isn't trying to dereference nor free
anything.

Any theories?

Regards,
Munawwar
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