I am getting this error message. “Node was not TRANSACTION in file e:\r\build\extragear\kmymoney-4.6.1-20110918\work\kmymoney-4.8.0\kmymoney\mymoney\mymoneytransaction.cpp line 53”. Any help would be appreciated.
When do you get this message? Is it when starting up? After adding or
editing a transaction? Do you have a backup of your data? Is this
message sent to the console, or a pop-up? After you get the error, can
you continue using KMyMoney, or does it crash?
However, before answering any of these questions, please upgrade
KMyMoney. We might be able to figure out why you are seeing the error,
but 4.8.0 is absolutely ancient in computer years 
and we would much
rather help you upgrade to a fully supported version.
Just for additional info, that file is the source file containing the
code which generates the error, but that does not really help much, as
it doesn’t tell us which node, or which piece of the data it doesn’t
like. It is quite possible there is a problem in your data file. Minor
additional question - is your data in a regular .kmy file on a local
hard drive, or somewhere else? Finally, if you have not already, make
a backup copy of your data file, to be sure you can recover, just in
case things get worse (which I do not expect to happen.)
This error is thrown when the list of transactions in the data file contains a node that is not a transaction. This points into the direction of a corrupted data file. Current versions (5.1.x) will show the same error, the code just moved to a different location. So simply updating the software will not really help here.
In case you use the .kmy file type: this is a gzip compressed XML file. I am not a Windows expert, but it could be that tools like WinZip or 7zip can decompress that file. As @ostroffjh pointed out: make a backup of it before you start playing around.
Decompressing will turn the data into readable XML and you can use tools like xmllint (don’t know if there is a Windows version) or online XML validators like XMLValidator to check if the structure is correct and what might be the problem.
The structure itself is no rocket science and one might be able to manually correct it using your favorite text editor (Notepad++ comes to mind). Unfortunately, no XSD for the KMyMoney structure exists (just in case you stumble upon that term).
If you want to know how the structure needs to look like: create a new KMyMoney file and make sure to save it as .xml (not .kmy). Using that filetype will skip the compression and you don’t need to manually decompress.
Hope that gets you started.