DLL Error Basics

What are DLL files?
Dynamic Link Library (DLL) files are dynamic code libraries that are used by Windows operating systems, device drivers, and various Windows-based applications to perform specific tasks on the computer. The popularity of DLL files is governed by the fact that it reduces the need to include the same code again and again in different applications. With DLLs, you just need to write the code once as a DLL, and then program your application to call on this DLL file whenever it needs to perform the specific task.
What causes DLL errors?
Because the number of DLL files on a Windows system is quite large, DLL errors can occur due to several reasons. Some of the most common causes of DLL errors are listed below:

• One or more DLL files required by an application or device driver are missing, corrupt or obsolete.
• A required DLL is overwritten by an older or incompatible version when you install an application. For instance, Msvcp71.dll and Msvcr71.dll errors may occur if the DLL files are overwritten or deleted when you install or uninstall an application using them.
• Problems or bugs in applications that are using the DLL file.
• Existence of multiple versions of same application on the system. For instance, msoe.dll error occurs due to the existence of both Outlook Express 5 and Outlook Express 6 versions on the same computer.
• There invalid or incorrect entries in the registry. For example, Shell32.dll error may occur due to problems in the registry.
• Virus and spyware infections.

If DLL errors become a common affair on a computer, the computer is said to be in DLL hell.
How to fix and prevent DLL errors?
If the DLL error starts occurring soon after you have installed a new application on your computer, it is quite likely that some important DLL files are overwritten by their older versions. In order to fix this problem, first try to check on this application�s Web site if any update for this new program is available. If it is there, updating your program might resolve the error. If it does not, try to look for a newer version of the overwritten DLL file on other computers or on the Web and copy them to their respective folders on the system. You may have to use the regsvr32 command to register the files on your system.