FDM is bundled with non-GPL Free Upload Manager (FUM) software by FreeDownloadManager.ORG.

FDM uses FUM's core module in order to provide users with upload functionality (Uploads tab).

FDM can be installed and used without FUM and its core module. In this case Uploads tab will not be available. Except this FDM will work as usual.

In order to create installer without the FUM bundle do the following steps:

1. Remove FUM bundle from [Files] section.

2. Remove from [Icons] section all FUM's entries.

3. Remove from [Registry] section all FUM's entries.

4. Remove from [Code] section all functions that has 'FUM' or 'Fum' in their names except ShutdownFdmAndFum_old and ShutdownFdmAndFum. 

5. Corrent InitializeSetup function: remove 'Free Upload Manager' text from message.

6. Correct ShutdownFdmAndFum_old and ShutdownFdmAndFum functions: remove FUM shutdown code and from lists of mutexes and correct msg box text. 

7. Correct ApplySelectedLanguage function.

8. Correct CurUninstallStepChanged.

9. Remove all calls to non-existing functions from code in [Code] section.

10. Remove from [Run] and [UninstallRun] all FUM's entries. 

I've got 'fdm-no_fum.iss' when did these steps (it's outdated now however).