Hi Niladri,
Are you getting this error msg in testing client or in production? if it was testing client then go to t-code PU00 ( delete personal number) and give the employee number to whon your getting this error msg. Then click execute. Once you execute,now system will list out all infotypes and clusters and ask you to select which infotype you need to delete. Here you have to select only the B2 clusters ( you can see this when you scroll down the infotype list) and execute. Now only the B2 cluster would have been deleted.that mean all time accounts and time balances deleted.
Now you run the time evaluation for this employee. I hope it should work.
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but when you attempt to do this in the production environment. Please consider the impact before deleting the cluster B2. and also take one employee first and check wether it's going fine. Since you have only 2 employees you can try this.
regards,
DInesh.