Error in security - sale transaction

Hi,

Im facing issues in the below scenario.

1. Created security class in FWZZ

2. Purchased 100 qty in the above class.

3.Below error while selling 50 qty .

Short position in accounting code 1001, val. area 001, ID No. IZA851824CH30, date
2012/12/10

1. Messageno. TPM_TRL062

TPM26 is showing security class position with qty 100 but still we are not able to sell 50 qty.

Recently we have migrated from UNIX to Windows and I doubt this is because of some infrastructure related issue.

Any help on this is highly appriciated.

Thanks in advance,

Venkat