Here are steps you can take to address this issue:

1. Check Compatibility:

   • Ensure that the versions of APCu and PCRE (Perl Compatible Regular Expressions) are compatible. Incompatibility between versions can lead to symbol lookup errors.

2. Recompile or Reinstall APCu:

   • If you compiled APCu manually, try recompiling it with the correct dependencies. If you installed it using a package manager, consider reinstalling it.

3. Check for Missing Dependencies:

   • Verify that both APCu and PCRE are installed on your system and are the correct versions.

4. Library Path Configuration:

   • Ensure that the paths to the libraries (apcu.so and pcre.so) are correctly set. They should be in the appropriate directories where the PHP interpreter can find them.

5. Dynamic Library Loading Order:

   • Check the order in which PHP loads dynamic libraries. Sometimes, a library that is loaded later might override a function from an earlier-loaded library. You can check the php.ini file for the extension directives.

6. Rebuild PHP with APCu Support:

   • If you are building PHP from a source, make sure to include support for APCu during the configuration and build process.

7. Update or Reinstall PHP:

   • If none of the above steps work, consider updating or reinstalling PHP. Make sure to use a version that is compatible with the APCu and PCRE versions you are using.

8. Check for Duplicate Libraries:

   • Verify that there are no duplicate copies of the apcu.so or pcre.so libraries on your system, as conflicting versions may cause issues.

9. Consult System Administrator or Hosting Provider:

   • If you're unable to resolve the issue, consult with your system administrator or hosting provider. They may have specific configurations or requirements for your environment.

Remember to back up your configuration and data before making significant changes to your server's software or libraries. This will help you recover in case anything goes wrong during the troubleshooting process.