(2,754) Argument 1 to GT is unset

Please help... 

PML Alert Summary:
Message: PML Error in method SETUPPOSITIONCONTROL : Index was outside the bounds of the array.
Line: In line 711 of PML function pipeeditor.PIPEEDITOR
Command: !this.headPosControl.setUpPositionControl()
Call-Stack:
01: Called from line 38 of PML function pipeworkpipecreate.EXECUTE
02: PML RELOAD FORM !!pipeEditor

Above error is popping up while opening pipe creation menu 

It occurred to me if you have both E3D2.1 and E3D3.1 on your computer, or if there is a conflict between different versions of the program

Thank you.

 E3D3.1 is installed in my PC.

But the project which was created in E3D 2.1 and is mapped to E3D 3.1 

According to your error message, the program is executing HeadPosControl error, error occurred in PIPEEDITOR.dll, try to find pipeEditor.pmlfrm in pmllib/design/forms line 771; Will! Enclosing headPosControl. SetUpPositionControl () is modified to! This. HeadPosControl. SetUpPositionControl (false), the next statement! This. TailPosControl. SetUpPositionControl () is the same. Save the change and enter PML RELOAD FORM !!pipeEditor in the E3D command window.

Thank you for your reply.

Error messgae is not coming for AVEVA supplied projects. It is coming only in the projects which are directly mapped from E3D2.1 projects.

might dbupgrade is required, upto some fix it will work properly, AVEVA Supplied projects are already upgraded it seems.