CodeAccessPermission problem

Hello everyone,

I have a class that queries for data with direct SQL. I execute a query and do a while-loop on my resultset.
In the while-loop itself I fill a file which needs to be stored on a specific location.

I am working for a couple months in AX so I still need to learn many things.

I started with the following code:
...

FileIoPermission    filepermission;
FileName    tempGeneratedFile;
AsciiIo    tempFile;
str    output;
;

filepermission = new FileIoPermission(tempGeneratedFile, 'w');
filepermission.assert();

tempFile = new AsciiIo(tempGeneratedFile, 'w');

... some logic / sql statement ...

while(resultSet.next())
{
    ... some logic for the lines that will be written in the file ...
    tempFile.write(output);
}

CodeAccessPermission::revertAssert();

...

Now when I compile this code above, i get the best practice: TwC: Assert usage of API AsciiIo.new because it is protected by Code Access Security.

I search on google for a solutions, but I can't make it disappear. I thought the CodeAccessPermission::revertAssert would do the thing, but it didn't.
I have 2 other classes that use similar coding and what I do extra there is set tempFile = null after the while-loop (I have read it somewhere) but that didn't help as well.

This best practice is not the worst thing to happen, but when I execute one of these classes in batch I get the following error (and batch status error) after full execution:
Request for the permission of type 'FileIoPermission' failed.
(S)\Classes\FileIoPermission\demand
(S)\Classes\WinAPIServer\getTempPath - line 13
...

So I search for this error, but I couldn't find a proper solution.

Does anyone has experienced this before and provide me a working solution ?

Thanks in advance,

Vincent