Hi, I've read through a lot of posts trying to solve my problem with no success. I've run 3CX successfully on an XP Pro desktop, then a Vista Home Premium Laptop for testing. Finally installed it on a Vista Ultimate x64 machine for commercial application thinking it would be as straight forward as the testing scenarios. However, core services failed to start (3CX assistant service) and the web interface (both versions) also failes quoting an internal server error - Line: 127 not showing the correct values. I've checked the event log which has the following information: Can anyone tell me what to do to get it working otherwise I'm going to tell this guy to get another computer! "TLOSS error SING error DOMAIN error R6029 - This application cannot run using the active version of the Microsoft .NET Runtime Please contact the application's support team for more information. R6028 - unable to initialize heap R6027 - not enough space for lowio initialization R6026 - not enough space for stdio initialization R6025 - pure virtual function call R6024 - not enough space for _onexit/atexit table R6019 - unable to open console device R6018 - unexpected heap error R6017 - unexpected multithread lock error R6016 - not enough space for thread data This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information. R6009 - not enough space for environment R6008 - not enough space for arguments R6002 - floating point not loaded Microsoft Visual C++ Runtime Library Runtime Error! Program: ... <program name unknown> Program: A buffer overrun has been detected which has corrupted the program's internal state. The program cannot safely continue execution and must now be terminated. Buffer overrun detected! A security error of unknown cause has been detected which has corrupted the program's internal state. The program cannot safely continue execution and must now be terminated. Unknown security failure detected!" Thanks in advance.