EMAIL activity in Oracle BPEL does not support single quotes

During compilation of an Oracle SOA BPEL project, I ran into an error related to the EMAIL activity.

Problem:

I received an error invalid syntax when building the project, but the error message did not tell me what the issue exactly was:

Error(782): The expression "concat(string('<br><table border='1px' style='bo ..." has invalid syntax - Expected: )	Project.bpel
D:\SOA\Code\Ahmed\Project\SOA\BPEL	Project.jpr

The contents of the "Expected:" field in the log was empty.

Solution:

In the body of the EMAIL activity, my HTML text included single quotes, as follows:

<br><table border='1px' style='border-collapse:collapse' cellspacing='0' cellpadding='0' width='50%'>...

Replace all single quotes with double quotes and the problem was resolved:

<br><table border="1px" style="border-collapse:collapse" cellspacing="0" cellpadding="0" width="50%">...