Hi German,
Since we no longer use NeatUpload the relevant settings are on the <httpRuntime element in web.config
In this case the error is not about the file size but the execution timeout, ie the upload is taking longer than current configuration allows.
You can adjust these 2 attributes to control file size and execution timeout:
<httpRuntime maxRequestLength="2097151" executionTimeout="3600" />
However in IIS 7.x file size is also controlled by:
<security>
<requestFiltering>
<requestLimits maxAllowedContentLength="31457280" />
</requestFiltering>
</security>
in the system.webServer section. We have something like the above in comments in web.config that may need to be uncommented and adjusted if you have problems based on file size that are not solved by the httpRuntime element. We have it commente dout because on some servers uncommenting it could cause errors if it is not allowed to configure that at web.config level.
Hope that helps,
Joe