This file has been reported to be part of a spyware/malware/trojan. It is likely that the problem you are experiencing is linked directly to the spyware/malware/trojan rather than an actual missing DLL-file and the recommended course of action is to first locate/remove the Malware. We do not recommend downloading this file.
DLL-Files.com Support says:
Part of: 'Mostrar Dialer'
This is a possible manual solution for you 'handyman-fixers' out there:
WARNING: Do this at your own risk. manually changing the registry could cause system critical errors if done incorrectly, the instructions below are not guaranteed to work on your particular system setup.
Please follow the instructions below if you would like to remove Mostrar Dialer manually. Please notice that you must follow the instructions very carefully and delete everything that is mentioned. In most cases the removal will fail if one single item is not deleted. If Mostrar Dialer remains on your system after stepping through the removal instructions, please double-check by stepping through them again.
1. Start the registry editor. This is done by clicking 'Start' then 'Run'. (The Run dialog will appear.) Type regedit and click OK. (The registry editor will open.)
2. Delete 'HKEY_LOCAL_MACHINE \ SOFTWARE \ Classes \ CLSID \ {582788CA-7014-4904-A4EE-6FB6108AFE8E}', if it exists.
3. Browse to the key: 'HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows \ CurrentVersion \ Run'
4. In the right pane, delete the value called 'MP3NumberOne' or 'ContentDownload', if it exists.
5. Exit the registry editor.
6. Restart your computer.
7. Start Windows Explorer and delete:
%SystemDir%\MSA64CHK.DLL
%SystemDir%\msapasrc.dll
Note: %SystemDir% is a variable (?). By default, this is C:\Windows\System (Windows 95/98/Me),
C:\WINNT\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).