You cannot convert your 32 bit softwares to 64 bit with help of any software.
But you also dont need to convert it because 64 bit architecture supports all 32 bit softwares.
Consider the Differences Between the 32-bit and 64-bit Data Models
The biggest difference between the 32-bit and the 64-bit compilation environments is the change in data-type models. The C data-type model for 32-bit applications is the ILP32 model, so named because the int and long types, and pointers, are 32-bit data types. The data-type model for 64-bit applications is the LP64 data model, so named because long and pointer types grow to 64 bits. The remaining C integer types and the floating-point types are the same in both data-type models.
Converting 32-bit Applications Into 64-bit Applications: The Problems
The principal cause of problems when converting 32-bit applications to 64-bit applications is the change in size of the int type with respect to the long and pointer types. When converting 32-bit programs to 64-bit programs, only long types and pointer types change in size from 32 bits to 64 bits; integers of type int stay at 32 bits in size. This can cause trouble with data truncation when assigning pointer or long types to int types. Also, problems with sign extension can occur when assigning expressions using types shorter than the size of an int to an unsigned long or a pointer.
To read further here is the source.
Source : http://www.oracle.com/technetwork/server-storage/solaris/ilp32tolp64issues-137107.html
This article tells you how to do the conversion with changes in code
Taken from: https://www.quora.com/How-do-I-convert-a-32-bit-software-into-a-64-bit
From my understanding, you have to modify the source code according to the above procedures by changing the variable types.
Plus I googled the error you're having may be unrelated to conversion.