What version of Sage 500 are you using?  If it is a supported version, have you contacted support?  Some of the things they may ask are:

• What operating system is the computer using? 
• Does this error occur on other machines or just this one. 
• Does the error occur for multiple users or specific users
• Is this a standalone machine or are you running through Terminal Server/Citrix

What version of Sage 500 are you using? Sage Line 500 Client v.60

• What operating system is the computer using?  Win 7 and win 10
• Does this error occur on other machines or just this one?  In all the machine
• Does the error occur for multiple users or specific users? multiple users
• Is this a standalone machine or are you running through Terminal Server/Citrix?   Running through Terminal Server where software installed with customizing module and reports. And accessing from client PC where software installed but customizing module and reports accessing from Server.

What version of Sage 500 are you using? Sage Line 500 Client v.60

• What operating system is the computer using?  Win 7 and win 10
• Does this error occur on other machines or just this one?  In all the machine
• Does the error occur for multiple users or specific users? multiple users
• Is this a standalone machine or are you running through Terminal Server/Citrix?   Running through Terminal Server where software installed with customizing module and reports. And accessing from client PC where software installed but customizing module and reports accessing from Server.

Hi Afzal,

Please note that this particular forum is for Sage 500 ERP, which is sold in the US.  Sage Line 500 is an entirely different product.  That sounds as though it may be a UK based product.  At this time, however, we do not have an online support group on Sage City for that product, so I would recommend calling your local support team for further assistance on this issue.

Thanks,

Derek

 the local support team raised their hand for assistance on this issue because this product is old. 

This system is working fine in Server but the only issue with the customize modules and reports that gives error while opening from client PC. 

This forum will be unable to assist you as Sage 500 ERP is a different product.  I did do a quick search and found the following link that may help you.

https://my.sage.co.uk/public/help/enterprise/erp1000-line500.aspx