not fixing it means you have paid good money for a cripple program.
As arturox indicated above, this invalid argument message is apparently something associated with Microsoft -- a simple Google search for the term will reveal very quickly that it affects a very wide range of programs across the board. So it is not that X4 is a 'cripple program', but it has in this instance, for a group of users, been crippled by something else.
After going through a dozen or more of the Goodle search findings, one common thread seems to be recent Windows updates which appear to have affected certain users of those various programs. One possible way of correcting things could be to ensure that your DirectX is fully up to date. DirectX must be updated manually, it is not part of the customary windows update process. You will find the most recent version here:
http://www.microsoft.com/download/en/de ... LSUS007776 . Download it, then create a folder on your system to extract the files into, because it will extract around 200 files, and I sure wouldn't want them running loose. Once extracted, locate inside the folder the DXSETUP.exe file and run it. Once it has finished installing you can delete the folder containing all the extracted files.
BTW, ignore the explanation on that page about it being for DirectX 9.0c and earlier versions. In the small print below it, you will see it is also for Windows 7 (DX 11) and Vista (VX 10). And after applying it, your DX will still have the same version number, but of course the build number will have been updated.
