First of all, use "sh ver" at MSFC router privileged mode to show config-register value at last line of console window output. This hex value can conntrol IOS finding and loading schedule. If it's ok (e.g. 0x2102), use command sh bootflash: and sh ru...
This thing could happen not only in some "patch cord" cases, but also because your switch has a GBIC support both MMF and SMF.As we know, Cisco now has 3 models of GBIC module: WS-G5484, WS-G5486 and WS-G5487. Data from Official Cisco documents says ...