I had problem when using Manager on my ubuntu, when i try to key in purchase order. The total amount become zero. I already key in inventory system to match it with purchase invoice for the cost amount and sales price, but when i key in at purchase invoice the price become zero.
Can you try to enter into the amount field simple number like 100 without any currency symbol or decimal point? Do you get the same issue?
ok…when i remove the decimal point at price…the problem seem go away…n everything back to normal…but when it had decimal point…the problem comes back… 
It means Manager wasn’t able to parse the number with decimal point. What’s your decimal point you are entering? A dot or comma?
A dot.
What’s your number, date format set to when you click Preferences in Manager?
i set it to Malaysia.
Try different country with similar format such as English (United Kingdom) to see if it fixes the issue.
ok…now my problem solved with changing into different format. thanks for your help…appreciate it~ 