Cannot open log file

When I am running a session am getting an error as :

Start workflow from task:
ERROR: Workflow [emp_wrk]:
Cannot open log file [C:Program FilesInformatica PowerCenter 7.1.1RepositoryServerWorkflowLogsemp_wrk.log]. System error is [2] [No such file or directory]. Please check the server log for more information.

Can anyone help me out.

[B]Question asked by visitor saikrishna[/b]

I need help with the error occurred while starting the workflow in Informatica Powercenter 7.1.1 .
Start workflow: Request acknowledged
Start workflow: ERROR: Workflow [wf_PhoneList]: Cannot open log file [C:\Program Files\InformaticaPowerCenter 7.1.1\Server\WorkflowLogs\wf_PhoneList.log]. System error is [2] [No such file or directory]. Please check the server log for more information.

Please help me with this error.